AU2007263328A2 - Process for the production of 2- [4 - ( 3- and 2-fluorobenzyloxy) benzylamino] propan amides - Google Patents

Description

WO 2007/147491 PCT/EP2007/005105 1 PROCESS FOR THE PRODUCTION OF AND 2-FLUOROBENZYLOXY) BENZYLAMINO) PROPAN AMIDES BACKGROUND OF THE INVENTION The present invention relates to a new process for the production of [4-(3-fluorobenzyloxy)-benzylamino]propanamide, i.e. safinamide (Ia) and (S)-2-[4-(2-fluorobenzyloxy)-benzylamino]propanamide, i.e. ralfinamide (Ib) and their salts, in high yields and very high enantiomeric and chemical purity.

This method is also very useful for their production in large quantites.

F

H

ON

safinamide 3-F ralfinamide 2-F Safinamide (NW-1015, FCE-26743A, PNU-151774E) is a sodium channel blocker, a calcium channel modulator, a monoamino oxidase B (MAO-B) inhibitor, a glutamate releasing inhibitor and a dopamine metabolism modulator.

Safinamide is useful in the treatment of CNS disorders, in particular of epilepsy, Parkinson's disease, Alzheimer's disease, depression, restless legs syndrome and migraine (WO 90/14334, WO 04/089353, WO 05/102300, WO 04/062655).

Ralfinamide (NW-1029, FCE-26742A, PNU-0154339E) is a sodium channel blocker useful in the treatment of pain conditions, including chronic pain and neuropathic pain, migraine, bipolar disorders, depressions, cardiovascular, inflammatory, urogenital, metabolic and gastrointestinal disorders (WO 99/35125, WO 03/020273, WO 04/062655, WO 005/018627, WO 05/070405, W005/102300, WO 06/027052).

SIt has now been discovered that the large scale preparations of safinamide and ralfinamide according to the methods described in the prior art, contain two undesired impurities, respectively, fluorobenzyl)-4-(3-fluorobenzyloxy)-benzylamino]propanamide (IIa) and 0 0 (S)-2-[3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)n benzylamino]propanamide (IIb), and their salt, in particular the I respective methanesulfonates (IIc) and (IId) NH2 NH2 H

H

(Ia) (IIb) This fact is of particular relevance because of the very high toxicity of the two impurities named above.

Many of the drug candidates fail in clinical trials because of unforeseen effects on human metabolism, or toxicity, due to unwanted impurities and, therefore, the elimination of such impurities in early pre-clinical phase is important and strongly desirable.

At preclinical level, the "drugability" of new compounds can be assessed using a very well established battery of in vitro assays, such as interaction with drug-metabolizing enzymes, cytotoxicity, metabolic stability and profiling, membrane permeability, intrinsic clearance and human ether-a-go-go related gene (HERG) channel blockade etc.

The Cytochrome P450 (CYP 450) system is the principal enzyme system for the metabolism of lipophilic xenobiotics, including drugs, carcinogens, and environmental pollutants. CYP 450 is a hemecontaining, membrane bound, multienzyme system that is present in many tissues but is present at the highest level in liver. In human liver, N-\Melboume\Cases\Pent\79000 -,9999\P7 g\ P H ep-ci firt.dWo 9/01/09 0it is estimated that there are 15 to 20 different xenobiotic-metabolizing SCYP 450 forms. So far, more than fourteen CYP gene families have been identified in mammals. Despite the existing high homology, extensive studies have revealed that each CYP family and subfamily has distinct roles in xenobiotic metabolism. Three CYP families CYP1, CYP2 and 0 CYP3 account for about 70% of human hepatic microsomes CYPs with c CYP3 accounting for approximately 30%. These CYPs are the major responsible for the metabolism of most marketed drugs.

SThe CYP1 family contains several members that include CYP1A1, C 10 CYP1A2 and CYP1B1 and they are involved in the metabolism of acetaminophen, clomipramine and imipramine.

The CYP2 family contains several subfamilies including CYP2A, CYP2B, CYP2C, CYP2D and CYP2E. The CYP2C subfamily contains at least seven members. CYP2C9 is responsible for the metabolism of ibuprofen, diclofenac, tolbutamide and torsemide. CYP2C19 is the major isoenzyme metabolizing diazepam and omeprazole. CYP2D6 has been shown to be responsible for metabolizing over 30% of the drugs on the market, including, antidepressants and cardiovascular and antipsychotic drugs.

In the CYP3 family, three isoforms have been identified in human liver.

Human CYP3A4 has been recognized to be the most important isoform in drug metabolism. To date, metabolism catalyzed by CYP3A4 is the major elimination route for nearly 50% of marketed drugs.

Because of their importance in drug metabolism, both CYP3A4 and CYP2D6 are often involved in drug-drug interactions and several clinically used compounds have been identified as potent inhibitor of these CYP 450 isoforms such as ketoconazole, terfenadine, erythromycin, miconazole propanolol and quinidine, respectively. This imposes a clear limitation on the use of these drugs.

A further problem, consisting in sudden death as a side effect of the action of non antiarrhytmic drugs, is a major pharmacological safety concern facing the pharmaceutical industry and the health regulatory N:\Melbourne\Caeo\Pacenc\79000-79999\P79432.AU\Specil\P79432.AU GH spec fUreL.doc 9/01/09 0authorities. In recent years, at least five blockbusters drugs (astemizole, Ssertindole, terfenadine, cisapride, grepafloxacin) have been withdrawn from the market due to reports of sudden death. In all cases, long QT Syndrome (LQTS), an abnormality of cardiac muscle repolarization, that is characterized by the prolongation of the QT interval in the 0 electrocardiogram, was implicated as a predisposing factor for "torsades de pointes", a polymorphic ventricular

IN

N:\Melbume\Ce.\Paent\79 -79999\P9432AU\Specis\P79432.AU GH opect firLAdoc 9/01/09 WO 2007/147491 PCT/EP2007/005105 4 tachycardia that can spontaneously degenerate to ventricular fibrillation and cause sudden death. Congenital LQTS can be traced back to several possible mutations resulting in defects in sodium channels, and two different potassium channels: the rapidly activating delayed rectifier (IKr) and the slowly activating delayed rectifier (IKs). Importantly, virtually every case of a prolonged duration of cardiac action potential related to drug exposure (acquired LQTS) can be traced to one specific mechanism: blockade of IKr current in the heart. This current, a major contributor to phase 3 repolarization at the end of QT interval, is conducted by tetrameric pores, with the individual subunits encoded by HERG. With blockade of HERG K channels widely regarded as the predominant cause of druginduced QT prolongation, early detection of compounds with this undesirable side effect has become an important objective in the pharmaceutical industry.

Compounds with strong inhibition of drug-metabolizing enzymes, in particular CYP 450 enzymes, and HERG channel blocking properties have a high probability to be toxic and that their development has to be stopped at an early-stage.

As shown in the Table 1 the impurities (IIa and lib), as the methanesulfonate salt (IIc and lid), strongly inhibit in the micro- and submicro-molar range CYP3A4, CYP2D6, CYP2C19, CYP2C9 and HERG currents and are highly cytotoxic, compared with safinamide methanesulfonate (Ic) and ralfinamide methanesulfonate (Id) with high purity degrees, synthetized using the process of this invention.

Table 1 HERG Cytotoxicity CYP3A4 CYP2D6 CYP2C19 CYP2C9 CYP1A2 Compound ICso, IC 50 ICso, IC50, ICso, ICso, ICso, pM pM pM LM M pM pLM Impurity 1.20 6.70 0.05 0.77 0.42 7.29 IIc Safinamide 27.0 248.0 40 40 23.85 40 methanesulfonate

I

Impurity 2.66 15.00 0.05 0.92 1.89 8.01 Ild Ralfinamide 18.0 300 40 40 40 40 methanesulfonate Table 2 shows comparative results (ICso) about the inhibition of the cytocrome CYP3A4 using highly pure safinamide and ralfinamide methanesulfonate, synthesized using the new process of this invention, with safinamide and ralfinamide obtained with the same process in the presence of 0.3% of the impurity IIc and lid, respectively.

When 0.3% of the impurities IIH and lid are added to highly pure safinamide and ralfinamide methanesulfonate, a significant decrease in ICso on CYP3A4 is observed in both cases meaning that the impurities contribute to a strong inhibition of the enzyme activity.

Table 2 Compound CYP3A4 ICs0oM Safinamide methanesulfonate Safinamide 18 methanesulfonate plus 0.3% lIc impurity Ralfinamide methanesulfonate Ralfinamide 7.76 methanesulfonate plus 0.3% lid impurity N:\Me1lboue\Caeo\Paent\7900-79999\P 9432.A\Specis\P79432.AU GH speci firaLdoc 9/01/09 As shown in Table 3 the impurity (IIc) increases, starting from 3 mg/kg ip, the mortality in the mice Maximal Electroshock (MES) test without any pharmacological activity, i.e. protection from convulsions.

Table 3

MES

Compound 3 mg/kg ip 10 mg/kg ip 30 mg/kg ip rottion dead/live poteon dead/live tection dead/live protection protection protection Safinamide methanesul- 50 0/10 100 0/10 100 0/10 fonate Impurity Ic 0 5/10 0 4/10 0 4/10 Table 4 reports that the impurity lid, when given p.o. at 10 and mg/kg, in the Maximal Electroshock test (MES) doesn't protect mice from convulsions if compared with the same doses of ralfinamide methanesulfonate.

Table 4

MES

Compound 10 mg/kg p.o. 20 mg/kg p.o.

Protection% Dead/live Dead/live Ralfinamide 60% 0/10 90% 0/10 methanesulfonate Impurity IId 0% 0/10 0% 0/10 Based on all these data, the impurities He and lid, present in safinamide and ralfinamide, respectively, synthesized with the process described in WO 90/14334 and by Pevarello et al in J. Med. Chem, N\Melbourne\Case\Patent\79000-79999\P 9432AU\Specie\P79432AU GH epec firstdoc 9/01/09 1998, 41, 579-590 show in vitro some undesirable features, such as cellular toxicity, strong inhibition of some isoform of CYP 450, HERG channel blockade and no protective activity in an "in vivo" model of epilepsy.

00 NJ\Melbourne\Caoes\PaLent\79000-79999\P79432.AU\Specio\P79432.AU GH spect firetdo 9/01/09 WO 2007/147491 PCT/EP2007/005105 7 One of the important aspects of CYP is the variation among different population groups. Variations in drug metabolism are of great importance in clinical studies. Considerable variation in the enzymatic activity of CYP3A4 and CYP2D6 has been demonstrated between different ethnic groups and even among different individuals in the same ethnic group. The difference in the CYP activity among individuals varies significantly, depending upon different isoenzymes. Changes in the CYP expression level of different individuals can cause variations in drug metabolism. More importantly, polymorphism can also result in CYP enzyme variants with lower or higher enymatic activity that leads to variations in drug metabolism. CYP2D6 polymorphism is a well-studied topic in drug metabolism. In clinical studies, pronounced variations between individuals was first found in the metabolism of antihypertensive and antiepileptic drugs. Elimination of CYP2D6 metabolized drugs is slower in those individuals who carry defective CYP2D6 alleles. Individuals with slow metabolism are classified as poor metabolizers while catalytically competent individuals are called extensive metabolizers The incidence of the PM phenotype in population of different racial origin varies: approximately 5 to 10% of Caucasians are of the PM phenotype, but only 1% in Asian population. CYP2C19 is another important polymorphic isoform that has clinical implications.

Taken into account these observations, a compound that does not interfere with CYP450 isoforms (neither inhibition nor induction) has a very low risk for drug-drug interactions in clinical practice and can be simply and safely prescribed by physicians.

In particular, drugs that not interfere with the cytochromes of the CYP450 system are particularly indicated for the therapeutical treatment of individuals that are classified as poor metabolizers (PM) or for the therapeutical treatment of patients who are concomitantly assuming other drugs which are known to interact with said cytochromes, such as ketoconazole, terfenadine, erythromycin, miconazole, propanolol and quinidine, and/or are known to have HERG channel blocking properties.

According to the common clinical practice, safinamide and ralfinamide WO 2007/147491 PCT/EP2007/005105 8 methanesulfonates (Ic and Id) are usually administered to the patient in need thereof for a long period of time, subdivided in several daily dose. This is particularly the case of therapeutical applications wherein the disease to be treated is: Parkinson's disease, Alzheimer's disease and restless legs syndrome (for the use of Safinamide) or chronic or neuropathic pain, cardiovascular or inflammatory disorders (for the use of Ralfinamide).

Although the daily dosage may vary according to the specific conditions and needs of the patients, the safinamide methanesulfonate daily dosage may usually range from 10 mg/day to 800 mg/day, while ralfinamide methanesulfonates daily dosage may usually range from 10 mg/day to Ig/day. Under these conditions, and in consideration of the data reported above, it is highly advisable to keep the level of the impurities (Ia) and (IIb) or the salts thereof, in particular the methanesulfonate salts (IIc) and (IId) in the pharmaceutical dosage forms of safinamide and ralfinamide or the salts thereof as low as possible, in any case lower than 0.03%, preferably lower than 0.01% by weight with respect to the amount of, respectively, safinamide and ralfinamide or the salts thereof, in particular the methanesulfonate salts.

Investigations and experimental studies carried out by the inventors have shown that safinamide and ralfinamide and the respective salts with pharmaceutically acceptable acids prepared according to the prior art methods contain an amount of the respective impurities (IIa) and (IIb) or the respective salts with pharmaceutically acceptable acids, such as (IIc) and (IId), that are higher than 0.03% by weight. Therefore, the above said products are unsuitable for safe therapeutical applications. In particular, pharmaceutical preparations containing safinamide or ralfinamide or the salt thereof with pharmaceutically acceptable acids, wherein the content of impurities (IIb), and the respective salts with pharmaceutically acceptable acids is not lower than 0.03%, preferably than 0.01% by weight with respect to the above said active substances, are not suitable as medicaments.

In this specification and claims the values of the above indicated limits, unless as otherwise specified, are to be intended as expressing the per cent ratio by weight of the "active substances", the effective content of the WO 2007/147491 PCT/EP207/005105 9 biologically active impurity (IIa, lib) with respect to the effective content of the therapeutically active substance (Ia, Ib).

The process described in this invention by strongly reducing the impurities leads to products with high chemical purity and safer biological profile.

Other impurities, barely detectable, derive from the very small quantities of 2- and 4-fluorobenzyl chloride and of 3- e 4-fluorobenzyl chloride which are contained in the commercially available 3-fluorobenzyl chloride and 2fluorobenzyl chloride respectively, used for the synthesis of 4-(3fluorobenzyloxy)benzaldehyde (IVa) e 4-(2-fluorobenzyloxy)benzaldehyde (IVb) intermediates for the preparation of, respectively, compounds (Ia) and (Ib).

According to the process described in the present invention safinamide and ralfinamide are obtained with high yields and high purity where the content of (S)-2-[3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)-benzylamino]-propanamide (Ila) and (S)-2-[3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)-benzylamino]propanamide (lib), and their salt, in particular with methanesulfonic acid (generically named "dibenzyl derivatives") in safinamide and ralfinamide or the salt thereof, in particular with methanesulfonic acid, is lower than or equal to 0.03%, preferably 0.01% (by weight).

The process object of the present invention starts from 4-hydroxybenzaldehyde and comprises the three following steps: a) O-benzylation of 4-hydroxybenzaldehyde with derivatives of the following general formula 3- or 2- F-C6H4-CH2-Y, where Y is a leaving group (Cl, Br, I, OSO2CH3 etc.); this O-benzylation is carried out under conditions which are highly selective for O-alkylation and gives 4-(3fluorobenzyloxy)benzaldehyde and 4-(2-fluorobenzyloxy)benzaldehyde of high purity; b) reductive alkylation of L-alaninamide, base or salt, with 4-(3fluorobenzyloxy)benzaldehyde and 4-(2-fluorobenzyloxy)benzaldehyde, where the reducing system is hydrogen gas and a heterogeneous catalyst, for obtaining, after crystallization, safinamide and ralfinamide respectively in very high enantiomeric and chemical purity; c) preparation of safinamide and ralfinamide salts with a pharmaceutically acceptable acid by salification of safinamide and 0 ralfinamide respectively, obtained in the preceding step.

SPharmaceutically acceptable acids are, for instance, selected from nitric, -s hydrochloric, hydrobromic, sulphuric, perchloric, phosphoric, methanesulfonic, p-toluensulfonic, acetic, trifluoroacetic, proprionic, glycolic, lactic, oxalic, malonic, malic, maleic, tartaric, citric, benzoic, 0 cinnamic, mandelic and salicylic acid.

cn A further object of this invention is to provide safinamide and IN ralfinamide or their salts with a pharmaceutically acceptable acid, Spreferably methanesulfonic acid, with a high purity degree, in particular C 10 with a content of the respective dibenzyl derivatives of the formula (IIa) or (IIb) or the salts thereof with a pharmaceutically acceptable acid, e.g.

the methanesulfonic acid, lower than 0.03%, preferably lower than 0.01% by weight (referred to the "active substances"), which is suitable for their use as medicaments.

Moreover, another object of this invention is to provide pharmaceutical formulations comprising safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, as the active agents wherein the content of the respective dibenzyl derivatives (IIa) and (IIb) or the salt thereof with a pharmaceutically acceptable acid, e.g. methanesulfonic acid, is lower than 0.03%, preferably lower than 0.01% (by weight) with respect to the above said active agents. These new pharmaceutical formulations were neither suggested nor achievable by applying the pharmaco-toxicological knowledge regarding safinamide and ralfinamide nor by using these active agents prepared according to the methods available in the state of the art.

Therefore, said pharmaceutical formulations comprising safinamide or ralfinamide or the salts thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, having the above said high purity degree constitute a further object of this invention.

The above said pharmaceutical formulations may optionally comprise one or more additional active agents, besides safinamide or ralfinamide N:\Melbournm\Caueo\Patent\79000-79999\P79432.AU\Speci P79432.AU CH speci first.doc 9/01/09 0 or the salts thereof with a pharmaceutically acceptable acid, preferably Smethanesulfonic acid, having the above described high purity degree.

For instance, a new pharmaceutical formulation useful for the Sadjunctive 00

(N

1^) 0C 0O N: \el bo-e\Calee\PacenL\79000-99 P79432 AU\pece\ P79432. AU GH epecl first.dc 9/01/09 WO 2007/147491 PCT/EP2007/005105 11 treatment of Parkinson's disease or restless legs syndrome may comprise one or more adjunctive Parkinson's disease active agent(s) such as those described in WO 04/089353 and WO 05/102300, preferably a dopamine agonist and/or levodopa and/or a catechol-O-methyltransferase (COMT) inhibitor, in addition to safinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, having the above said high purity degree.

As a further example, a new pharmaceutical formulation according to this invention useful for the treatment of pain conditions, including chronic pain and neuropathic pain, and migraine may contain a further active agent such as gabapentin and pregabalin or a pharmaceutically acceptable salt thereof as described in EP 1423168, in addition to ralfinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, having the above said high purity degree.

The pharmaceutical compositions containing high purity degree safinamide or ralfinamide according this invention can be prepared by conventional procedures known in the art, for instance by mixing the active compounds with pharmaceutically, therapeutically inert organic and/or inorganic carrier materials. The compositions of the invention can be in liquid form, e.g. in the form of a solution, suspension, emulsion; or in solid form, e.g.

tablets, troches, capsules, patches.

Suitable pharmaceutically, therapeutically inert organic and/or inorganic carrier materials useful in the preparation of the composition of the present invention include, for example, water, gelatine, arabic gum, lactose, starch, cellulose, magnesium steareate, talc, vegetable oils, polyalkyleneglycols, cyclodextrins and the like. The pharmaceutical compositions of the invention can be sterilized and may contain, besides the active ingredient(s), further components well known to the skilled in the art, such as, for example, preservatives, stabilizers, wetting or emulsifying agents, e.g. paraffin oil, mannide monooleate, salts to adjust osmotic pressure, buffers and the like.

A further object of this invention is to provide a method for treating CNS disorders, in particular epilepsy, Parkinson's disease, Alzheimer's disease and restless legs syndrome, comprising administering to a patient in need WO 2007/147491 PCT/EP2007/005105 12 thereof an effective amount of high purity degree safinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, having a content of dibenzyl derivative (IIa) or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, lower than 0.03%, preferably lower than 0.01% by weight (referred to the "active substances"). Said method includes treating Parkinson's disease or restless legs syndrome by administering to a patient in need thereof an effective amount of the high purity degree safinamide described above, optionally in conjunction with one or more Parkinson's disease active agent(s) as described in WO 2004/089353, such as, for instance, a dopamine agonist and/or levodopa and/or a catechol-Omethyltransferase (COMT) inhibitor.

Moreover, a further object of this invention is to provide a method for treating pain conditions including chronic pain and neuropathic pain, migraine, bipolar disorders, depressions, cardiovascular, inflammatory, urogenital, metabolic and gastrointestinal disorders comprising administering to a patient in need thereof an effective amount of high purity degree of ralfinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, having a content of dibenzyl derivative (lib) or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, lower than 0.03%, preferably lower than 0.01% by weight (referred to the "active substances").

The above said method includes treatment of pain conditions, including chronic pain and neuropathic pain, and migraine with high purity degree ralfinamide or a salt thereof with a pharmaceutically acceptable acid, preferably methanesulfonic acid, optionally in conjuction with gabapentin or pregabalin.

PRIOR ART In WO 90/14334, and in the paper by Pevarello et al. in J. Med. Chem., 1998, 41, 579-590, a three steps process for the preparation of benzyloxybenzylamino-alkanamides is described: a) synthesis of the intermediate 4-benzyloxybenzaldehydes by Obenzylation of the corresponding 4-hydroxybenzaldehydes with the

I

0 suitable benzyl chlorides b) reductive alkylation of a-amino-amides with 4-benzyloxy- -s benzaldehydes using sodium cyanoborohydride as a reducing 0 agent as schematically shown here below 00 23 C CHO R 4 R RR r CHO H NaBHCN N RR+ N R R I II R 0 R 0 where R represents, among other substituents, 3-F and 2-F; R 1 represents, among other substituents, hydrogen; R 2 represents, among other substituents, hydrogen; R 3 represents, among other substituents,

CH

3 both R 4 and R 5 represent, among other substituents, hydrogen.

In particular, as far as safinamide and rafinamide preparation is concerned, the reductive alkylation is the reductive alkylation of Lalaninamide with 4-(3-fluorobenzyloxy)benzaldehyde and 4-(2fluorobenzyloxy)benzaldehyde respectively as shown here below CHO H2 N NH2 NH2 R 0 R R 3-F-benzyloxy safinamide (la) R 2-F-benzyloxy ralfinamide (Ib) In J. Med. Chem. (Pevarello et 1998, 41, 579-590 yields of 45% and for the preparation of safinamide and ralfinamide methanesulfonate respectively, are reported, starting from the corresponding (fluorobenzyloxy)benzaldehydes.

The process described in WO 90/14334 and in the above cited paper is the same and provides a one-pot system where the iminoalkylation and the reduction are made in the same reactor. The suitable aldehyde is N:\Melboume\Caoe@\Paten79000-79999U GHp cl rirat.dM 9/0I/09 1 Sadded all at once to a mixture of L-alaninamide hydrochloride, sodium cyanoborohydride, methanol and powdered molecular sieves.

c- According to Pevarello et al., in Org. Prep. Proc. Int. 1996, 28, 179-183 0 (where the synthesis of some a-benzylaminoamide derivatives by reductive alkylation is described), use of an a-aminoamide as 00 hydrochloride is important for the formation of the iminium ion in place Sof the corresponding imine, as the iminium ion reacts more easily with

IO

(C sodium cyanoborohydride than with the aldehyde carbonyl group.

SAccording to above authors, the one-pot procedure seems to avoid NC 10 Schiff-base racemization problems and the molecular sieves speed up the reaction (although the yields are poor).

The cyanoborohydride is the only reducing agent utilized, and it seems that this choice is due to its low reactivity and its selectivity (see Review "Sodium Cyanoborohydride- A Highly Selective Reducing Agent for Organic Functional Groups" C.F. Lane, Synthesis 1975, 132-146 which makes it able to distinguish between the protonated Schiff base and the starting aldehyde.

The synthesis described in the paper by Pevarello et al. provides the isolation of the products by column chromatography, followed by conversion into the corresponding salts by treatment with acids. No information is provided about the enantiomeric and/or chemical purity of both safinamide and ralfinamide and/or their salts.

The method described in the prior art suffers from many drawbacks, that limit its use on large scale; herebelow some examples of said drawbacks are listed: formation of cyanides; formation of boron derivatives, difficult to remove from the active principles; use of powdered molecular sieves which are physically changeable and expensive; low yields; N:\Melbourne\CaBee\Patent\79000-P7999\P79432.AU\Secn\P79432.AU GH speci filr.doc 9101/09 14A 0- low final product concentration in the reductive alkylation reaction mixture (about 2-3% weight/volume S- isolation of the products by column chromatography, which is O considered a troublesome and expensive purification method when large scale preparations of active agents through chemical synthesis O 00 0' N \Mel boume\Ca\P 790009999\P32 P79432AU *pecl fir.tdoc 9/01/09 WO 2007/147491 PCT/EP2007/005105 are involved.

Moreover, as shown in the examples which follow this description, the products obtained according to the methods described in the prior art contain an amount of impurities (IIa), (lib), (IIc) or (IId) which is higher than 0.03% by weight with respect to the respective active substance (Ia), (Ic) or In addition, it has been shown that it is difficult to eliminate said impurities from the final product safinamide and ralfinamide or their salts, by using commonly known purification methods such as crystallization from solvents or chromatography, which in any case imply a reduction of yields.

SYNTHESIS OF THE 4-(FLUOROBENZYLOXY)-BENZALDEHYDE

INTERMEDIATES

According to the known methods, the fluorobenzyloxy-benzaldehydes intermediates for the synthesis of safinamide and ralfinamide are obtained by benzylation of 4-hydroxybenzaldehyde in a basic medium, that is by benzylation of phenol salts which, being ambident nucleophiles, give two different products, i.e. the desired O-alkylated derivatives and the undesired C-alkylated derivatives.

It has been effectively found that the fluorobenzylation of 4hydroxybenzaldehyde with 3-fluorobenzyl chloride, performed according to the prior art, gives the 4-(3-fluorobenzyloxy)benzaldehyde (IVa) as the main product together with 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde (Va) that derives from the alkylation of both the hydroxy group in position 4 and carbon atom in position 3 of the 4-hydroxybenzaldehyde. The same happens in the fluorobenzylation of 4-hydroxybenzaldehyde with 2fluorobenzyl chloride according to the following scheme: WO 2007/147491 PCT/EP2007/005105 X CO

HO"

(IIIai): 3-F (Ilbi): 2-F 3-F 2-F The reductive alkylation of L-alaninamide with an aldehyde which contains the di-alkylated impurity gives a safinamide or ralfinamide end product which is also impure of the respective di-alkylated compound, the di-benzyl derivative, whether as a free base (Ha) or (IIb) or a salified compounds preferably with methanesulfonic acid (IIe) or as shown in the following scheme:

F

O'Q

2) CHSO,H

CH

3

SOH

3-F 2-F (IIc): 3-F (IId): 2-F Other pharmaceutically acceptable acids, e.g. nitric, hydrochloric, hydrobromic, sulphuric, perchloric, phosphoric, methanesulfonic, ptoluensulfonic, acetic, trifluoroacetic, proprionic, glycolic, lactic, oxalic, malonic, malic, maleic, tartaric, citric, benzoic, cinnamic, mandelic and salicylic acid. can be used in the place of the preferred methanesulfonic acid.

The mono-alkylated derivative (safinamide or ralfinamide) and the WO 2007/147491 PCT/EP2007/005105 17 corresponding di-alkylated impurities have similar chemical-physical properties and this makes difficult the purification of safinamide and ralfinamide with traditional methods.

Furthermore the known methods suffer from these additional drawbacks: 1) the use of a lower alcohol as a solvent; in basic conditions, the solvent, for example methanol, can act itself as a nucleophilic reagent and gives, with 3- or 2-fluorobenzyl chloride a certain amount of methyl-fluorobenzyl-ether; 2) the extraction of the final product with a water-immiscible organic solvent is possible only after the alcoholic reaction solvent has been eliminated from the reaction mixture.

It has now been found that by using the above said prior art methods, in order to obtain a final product of formula (la) or (Ib) wherein the content of the respective impurity (Ia) or (IIb) is lower than 0.03% (by weight), it is necessary to drastically purify the intermediate 4-(3fluorobenzyloxy)benzaldehyde (IVa) or 4-(2-fluorobenzyloxy)benzaldehyde (IVb) to reduce content of the respective impurities of formula (Va) and (Vb).

Said purification is preferably carried out by submitting the reaction products to crystallization, more preferably by adding to a solution of the crude compound (IVa) or (IVb) in an inert organic solvent a miscible inert organic non-solvent. The organic inert solvent is preferably selected from the aromatic hydrocarbons and, more preferably, is toluene. The miscible inert organic non-solvent is preferably selected from the lower aliphatic hydrocarbons, more preferably is n-hexane. A further crystallization procedure may consist in dissolving the above said compounds (IVa) or (IVb) into a hot solvent, e.g. cyclohexane or a di(C3-C4)alkyl ether, such as diisopropyl ether at reflux, and then cooling the solution at room temperature, preferably at 10-15°C, most preferably, with inducing crystallization by addition of pure crystals of the pure compound (IVa) or (IVb).

According to one aspect of this invention, it has now surprisingly been found that when the reaction between an alkylating agent of formula (IIIa) or (IIIb) (see the scheme below where the F atom is in position 2 or 3 and Y is a leaving group such as, for example, Cl, Br, I, OSO2CH3, OSO2CsH4- 0pCH3, etc.) and 4-hydroxybenzaldehyde, is carried out under phase-

(N

c transfer conditions, the corresponding 4c- (fluorobenzyloxy)benzaldehydes are obtained in high yields and with very low level of C,O-bis-alkylated impurities.

00 cHO FCHO F S+ vent Base H Catalyst HOa (Ilia): 3-F (IVa): 3-F c N (IIIb): 2-F (IVb): 2-F This new fluorobenzylation of 4-hydroxybenzaldehyde under phasetransfer conditions can be made both in a solid/liquid system, where in the liquid organic phase the reagents and the phase-transfer catalyst are dissolved and the solid phase is constituted by the inorganic base or the 4-hydroxybenzaldehyde salt (possibly generated in situ from 4hydroxy-benzaldehyde and the inorganic base itself), and in a liquid/liquid organic/aqueous system where the inorganic base is dissolved in the aqueous phase.

A preferred system is the solid/liquid system wherein the inorganic base is preferably selected from Na2CO3, K 2

CO

3 KOH, NaOH.

The organic solvents used in the reaction, both in the case of the liquid/liquid system and of the solid/liquid system, can be dialkyl ethers such as, for example, di-tert-butyl ether, ethyl-tert-butyl ether, or aromatic hydrocarbons such as, for example, toluene, ethylbenzene, isopropylbenzene and xylenes. All these solvents can be easily recovered by distillation.

The phase-transfer catalysts employed can be quaternary ammonium or phosphonium salts such as, for example, tetrabutyl ammonium bromide, tetradecyltrimethyl ammonium bromide, hexadecyltributyl phosphonium bromide, tricaprilylmethyl ammonium chloride (Aliquat), N:\Mel boume\Coee\PenLt\7900O-79999\P79432AU\Spec,\P79432.AU GM speci trsetdoc 9/01/09 0 methyltrialkyl (Cs-C o)ammonium chloride (Adogen), the tetradecyltrimethyl ammonium bromide being the preferred one.

Also polyethyleneglycols of low molecular weight can be used as phasetransfer catalysts such as, for example, PEG-200 (CAS 25322- 68-3) or PEG-400 (CAS 25322-68-3).

0 The quantity of phase-transfer catalyst used is between 0.02-1 mol per c mole of 4-hydroxybenzaldehyde, preferably between 0.1-1 mol per mole 1 of 4-hydroxybenzaldehyde as, in these conditions, the quantity of the C,O-bis-fluorobenzylated impurities may result to be less than 0.03%, CN 10 preferably equal to 0.01% or less by weight.

The ratio between the alkylating agents of formula (IIIa) or (IIIb) and 4hydroxybenzaldehyde is comprised between 0.6 and 1.5, the preferred one being between 0.9 and 1.1.

The reaction temperature is comprised between 60 °C and 160 the preferred interval being between 80 °C and 120 °C.

The reaction time is generally comprised between 4 and 8 hours.

The reaction yields are very high, as a rule more than The reaction productivity, i.e. the concentration of the reaction products in the reaction mixture is very high in the reaction condition described, normally is more or equal to 25% (weight/volume).

SYNTHESIS OF SAFINAMIDE AND RALFINAMIDE BY REDUCTIVE ALKYLATION OF a-AMINOAMIDES The state of the art would suggest to the expert in the field that the reductive alkylation of a-amino-amides with or 2fluorobenzyloxy)benzaldehydes using hydrogen and a heterogeneous catalyst as a reducing agent, should not be suitable for the preparation of safinamide and ralfinamide because of the incompatibility among the reagents and the final products and the reduction conditions.

In fact, it is well known how easily benzaldehydes are reduced to benzyl alcohols or even to the corresponding hydrocarbons, as well as it is known that the conditions which should be used to perform a reductive N:\Melboune\Caucu\PaLen\79O00-79999\P79432.AU\Spci.\P79432.AU GH spect I iC.doc 9/01/09 0 alkylation with hydrogen and a heterogeneous catalyst, are normally the Ssame conditions used to break the bonds between a benzylic carbon atom and heteroatoms like nitrogen or oxygen, the kind of bonds that are present both in safinamide and ralfinamide and in their precursors.

In fact, the benzylic group is normally employed as a protecting group 0 of

IND

N;\Melboume\CaseB\Patent\79000-79999\P79432.AU\Speci\P79432.AU OH epeci firea.doc 9/01/09 WO 2007/147491 PCT/EP2007/005105 phenols or amines (see "Protective Groups in Organic Synthesis", T.W.

Greene and P.G.M. Wuts, 3 rd Edition, 1999, John Wiley Sons,Inc.) because of the easiness of its introduction and successive removal by catalytic reduction.

In the reductive alkylation for obtaining safinamide and ralfinamide, one could expect the formation of many by-products, some of which are reported here below: F F F SOH HO 0 FO O H The fact that safinamide and ralfinamide have been obtained in very high yields and purity by reductive alkylation of L-alaninamide, with or 2fluorobenzyloxy)benzaldehyde, using hydrogen and a heterogeneous catalyst as a reducing system, is a surprising and innovative aspect of this synthetic procedure.

Moreover, the reaction conditions which are used according to this procedure are easily applicable to the production in bulk.

The reductive alkylation, object of the present invention, is performed in two steps: a) formation of the Schiff base b) catalytic reduction of the Schiff base The two steps can be performend in succession in the same reactor (one pot reaction) either with, or without, isolation of the Schiff base, in both cases with high yields.

In the case of isolation of the Schiff base, the experimental conditions applied for its formation allow to obtain the isolated Schiff base in the form of a precipitate in high yields and very pure form.

The Schiff base preparation is suitably performed in an organic protic solvent, that must be inert vs. the reagents and the products and also inert WO 2007/147491 PCT/EP2007/005105 21 vs. the reduction conditions of the iminic double bond, such as for example, a (Ci-Cs) lower alkanol, preferably methanol, ethanol and isopropanol.

The formation of Schiff base must be complete and this is a relevant factor for having high yields in the subsequent catalytic reduction step. It is therefore preferable to isolate the Schiff bases (VIa) and (VIb) before performing the reduction of the iminic double bond.

FO& CH=N'

NH

2 (VIa):3-F (VIb):2-F The isolated imino compounds (VIa) and (VIb) are useful intermediates for the preparation of safinamide and ralfinamide, respectively, according to this invention.

Alternatively one can favour the iminoalkylation reaction completion, by operating under such conditions as to cause the precipitation of the imino compounds (VIa) and (VIb) and to submit to the catalytic reduction the suspension containing the intermediate imino derivative.

The ratio between L-alaninamide (base or salt) and or 2fluorobenzyloxy)benzaldehyde can be 1:1 but also a 10% excess of Lalaninamide can be advantageusly used.

The L-alaninamide may be introduced either as a free base or as an acid addition salt thereof. Preferably, it is introduced in the reaction mixture as a salt, most preferably as hydrochloride salt, together with the stoichiometric amount of a base, preferably a tertiary amine such as, for example triethylamine or diisopropylethylamine.

The reaction temperature in the preparation of the Schiff base is comprised between 0 °C and 60 OC, preferably between 20 *C and 30 °C.

0The reaction times are comprised between 1 hour and 15 hours, preferably between 4 hours and 6 hours.

c= The reduction of the Schiff base with hydrogen and a heterogeneous a catalyst is started only when the Schiffs base formation is completed: if it is started before, secondary reactions become important, sometimes 0 prevalent, with loss in yields and purity. One of these secondary reactions, the more important, causes the formation of benzylic alcohols IN by reduction of the carbonyl group of the (fluorobenzyloxy)benzaldehyde Sof choice.

C 10 The preferred heterogeneous catalysts are nickel, rhodium, palladium or platinum catalysts, on an inert support such as, for example, carbon, alumina and silica, preferably carbon and alumina, and are used in a quantity comprised between 2% and 20% of the 4-(3-or 2fluorobenzyloxy)benzaldehyde, preferably between 5% and Platinum and palladium catalysts are the most preferred.

Platinum on active carbon, in particular, gives excellent results both in terms of yields, which are nearly quantitative, and selectivity, as only the iminic double bond is reduced while the bond between the benzylic carbon atom and the heteroatoms remain unchanged. It was found that safinamide and ralfinamide are surprisingly stable in the reduction reaction conditions and this is an important element in industrial production of large quantities of safinamide or ralfinamide, as an incidental reaction time prolongation wouldn't damage the final products.

The best results were obtained with wet 5% Pt/C (50% H 2 0) and in particular with 5% Pt on carbon powder by Engelhard Rome, Italy.

The hydrogenation reaction is normally performed under a hydrogen pressure comprised between 1 bar and 10 bars, preferably between 3 bars and 6 bars and at temperature comprised between 10 °C and preferably between 25 °C and 40 °C.

N:\Melboumr\Casee\Patent\79000-79999\P79432.AU\SpeclB\P79432.AU GH speci first.doc 9/01/09 22A 0 The reduction times can vary from 1 hour to 20 hours, according to Stemperature, pressure, concentration, turbulence, etc., all factors well known to those skilled in the art.

The best results were obtained with reaction times of 4-6 hours.

At the end of the reaction the catalyst is recovered by filtration and 0 reutilized or regenerated: the reaction solvent is distilled under reduced

IND

N:\elboumne\Caea\Pae, \79000-7999\P9432.AU\SpeC.\P9432.AU GH *pecl firotdOC 9/01/09 WO 2007/147491 PCT/EP2007/005105 23 pressure, the residue is dissolved in water-immiscible organic solvent and the inorganic salts are removed by washing with water.

The final raw safinamide or ralfinamide are recovered by removing by distillation the organic solvent wherein they are dissolved.

The raw safinamide or ralfinamide are then purified by crystallization. The crystallization is preferably carried out by adding to a solution of the respective crude compound of formula (Ia) or (Ib) in an inert organic solvent a miscible inert organic non-solvent. The organic inert solvent is preferably selected from aromatic hydrocarbons such as benzene, toluene, dimethyl benzene and ethylbenzene and lower alkyl acetates and, more preferably, is ethyl acetate. The miscible inert organic non-solvent is preferably selected from the lower aliphatic hydrocarbons, such as hexane and heptane, and cyclohexane, more preferably is n-hexane The bases, are then transformed into the desired salts according to known methods, in particular they are transformed into methanesulfonate salt, which has the physical/chemical properties (stability, granulometry, flowability etc.) suitable for the subsequent formulation into a pharmaceutical preparation for use as medicament.

EXAMPLE 1 Preparation of purified 4-(2-fluorobenzyloxy)benzaldehyde (IVb) by phase transfer catalysis A mixture of 2-fluorobenzyl chloride (5 kg, 34.58 mol), 4-hydroxybenzaldehyde (3.9 kg, 31.94 mol), potassium carbonate (4.3 kg, 31.11 mol) and tetradecyl trimethylammonium bromide (0.41 kg, 1.22 mol) in toluene kg) is slowy brought, under stirring and under nitrogen, to reflux temperature and refluxed for 6h.

The solution is then concentrated at room pressure, 3 kg of toluene are added and distilled off and this procedure is repeated once again.

The heterogeneous mixture is then cooled to room temperature and the solid is eliminated by filtration. The residual solvent is then eliminated under reduced pressure and to the oily residue 1.2 kg of toluene are added.

The mixture is heated to about 40 oC and seeded with a few grams of pure 4-(2-fluorobenzyloxy)benzaldehyde.

0 The heterogeneous mixture is stirred for 15 minutes at 35-40 °C and then additioned of n-hexane (9 kg) at this temperature, in 30 minutes.

After cooling to 0-5 "C and stirring for a further hour at this temperature the solid is collected by filtration and dried under reduced pressure to give 6.5 kg (87.6% yield) of 4-(2- 0 fluorobenzyloxy)benzaldehyde; m.p. 56.7 °C (DSC, 5 °C/min).

C The above reaction is repeated on a 1:100 scale by using 39 g (0.319 mol) of 4-hydroxybenzaldehyde as the starting material and following Sthe above described procedure, with the exception that, after C 10 elimination of the reaction solvent and addition of toluene to the oily residue, the obtained mixture is heated to about 30-35 (instead of and, after seeding with a small amount of pure 4-(2fluorobenzyloxy)benzaldehyde, the heterogeneous mixture is stirred for minutes at 30 °C (instead of 35-40 0 C) before adding n-hexane.

The yield is 66.8 g of 4-(2-fluorobenzyloxy)benzaldehyde, m.p.

56.7 °C (DSC, 5 "C/min), having a GC purity of 92.2 (area see Example 16A) and a 3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzaldehyde content 0.01% by weight determined by GC (see Example 16B).

The yields reported in this and in the following Examples, when no otherwise specified, are intended as molar yields.

1.1 Further purification of 4-(2-fluorobenzyloxy)benzaldehyde by crystallization One kilogram of the product prepared according to the procedure described in Example 1 is dissolved in 2 kg of diisopropryl ether at reflux under stirring.

The solution is cooled to 50-55 °C in 10-15 minutes and seeded with a few grams of pure 4-(2-fluorobenzyloxy)benzaldehyde.

The suspension is cooled to 10-15 °C during 45-60 minutes and stirred for an additional hour.

NJ\Melbcume\Cases\Parto, \7900-79999\P79432.AU\Spece\P79432AU G spedl fot.do 9/01109 0 The precipitate is finally collected by filtration, washed with cool diisopropyl ether (0.2 kg) and dried under reduced pressure to give 0.93 -s kg of 4-(2-fluorobenzyloxy)benzaldehyde with GC purity of 99.8 (area see Example 16A) and a content of 3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzaldehyde (Vb) of 0.005% by weight determined by 0 GC according to Example 16B.

N

1.2 Preparation of 4-(2-fluorobenzyloxy)benzaldehyde (IVb) by phase Stransfer catalysis (PTC) using different catalysts.

CN 10 4-(2-fluorobenzyloxy)benzaldehyde is prepared by alkylation of 4hydroxybenzaldehyde (0.39 g) with 2-fluorobenzyl chloride by following the same procedure of Example 1, but using three different phase transfer catalysts.

The results are reported in the following Table 4.

TABLE 4 Experiment Phase %Vb %Yield Transfer Catalyst

PCT

1.2 Tetrabutyl fosphonium 0.03 85.0 bromide 1.2 Aliquat 336* 0.03 88.8 1.2 PEG 400 0.14 96.0 Aliquat 336: tricaprylylmethylammonium chloride %Vb: content of 3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde by weight) The content of Vb is determined by GC according to Example 16B.

M;\Melum\C\Pen 9000-9999\ P7943AU\Sec.\P7942.AUON Spei fidoc 9/01/09 1.3 Preparation of 4-(2-fluorobenzvloxylbenzaldehyde I1Th) by phase transfer catalysis (PTC) in gylene.

4-(2-.fluorobenzyloxy)benzaldehyde is prepared in 86.6% yield with a content of 3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde of 0.02% by weight determined by GC (see Example 16B)by reacting 4- 00 hydroxybenzaldehyde (0.39 g) with 2-fluorobenzyl chloride according to

(N

the N:\Melboume\Case.\Patet\79OOO-79999\P79432.AU\SpeCi,\P79432AU GH opeci ftrst.doc 9/01/09 WO 2007/147491 PCT/EP2007/005105 26 same procedure of Example 1, but replacing toluene with xylene as the solvent.

1.4 Preparation of 4-(2-fluorobenzyloxy)benzaldehyde IIVbj by phase transfer catalysis using potassium hydroxyde as a base 4-(2-Fluorobenzyloxy)benzaldehyde is prepared in 86.7% yield with a content of 3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde of 0.51% by weight determined by GC (see Example 16B) by reacting 4hydroxybenzaldehyde (0.39g) with 2-fluorobenzyl chloride, according to the same procedure of Example 1, but using potassium hydroxyde (0.35 mol) instead of potassium carbonate.

This product may be further purified by crystallization according to Example 1.1.

1.5 Preparation of 4-(2-fluorobenzyloxy)benzaldehyde (IVb) by phase transfer catalysis using 2-fluorobenzyl bromide 4-(2-Fluorobenzyloxy)benzaldehyde is prepared in 88.6% yield with a content of 3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde of 0.07% by weight determined by GC (see Example 16B) by reacting 4hydroxybenzaldehyde (15.6g) with 2-fluorobenzyl bromide instead of 2fluorobenzyl chloride according to the same procedure of Example 1.

EXAMPLE 2 Preparation of (S)-2-[4-(2-fluorobenzvloxy)benzylaminolpropanamide (ralfinamide, Ib) of high purity degree (one pot reaction) An autoclave is loaded with 4-(2-fluorobenzyloxy)benzaldehyde (2.0 kg, 8.69 mol) prepared according to Example 1, and then a solution prepared apart of L-alaninamide hydrochloride (1.2 kg, 9.63 mol) and triethylamine (0.97 kg, 9.63 mol) in methanol (9.5 kg) is added thereto.

The mixture is stirred at 20-25 "C for about 1 hour and then, after seeding it with a few grams of (S)-2-[4-(2-fluorobenzyloxy)benzylideneamino] propanamide, the stirring is continued for additional 15 minutes. To the stirred heterogeneous mixture, methanol (1.6 kg) and wet (50% H20) Pt/C (Engelhard cod.Escat 22, Engelhard Rome, Italy) (0.28 kg) are WO 2007/147491 PCTIEP2007005105 27 then added at 20-25 °C.

The air is purged from the autoclave with nitrogen and then hydrogen is introduced at 5.0 bar and the pressure is maintained at this value during the hydrogenation course.

After 5 hours at 30-35 °C the reaction mixture is cooled to 15 °C and, after addition of methanol (4.8 kg) and heating to 40-45 °C the suspension is filtered and the solid is washed with methanol (1.6 kg).

The solvent is eliminated under reduced pressure at about 30 °C and the residue is additioned of water (5 L) at 20-25 °C on cooling and under stirring, as the water addition is an exothermic process. The heterogeneous mixture is further cooled to 15-20 kept at this temperature for 1 hour and then filtered. The collected solid is washed with cool water (4 L) and dried under reduced pressure to give 2.23 kg (85.0% yield) of ralfinamide with a HPLC purity of 98.8 (area%) determined according to the method of Example 17A and a C,O-dialkylated (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)-benzylamino]propanamide content of 0.01% by weight determined by HPLC, according to the method of Example 17B.

2.1 Preparation of (S)-2-[4-(2-fluorobenzyloxy)benzylaminol propanamide (Ib) of high purity degree by using a palladium catalyst A mixture of 5 g of 4-(2-fluorobenzyloxy)benzaldehyde, prepared according to the Ex. 1 and the corresponding amount L-alaninamide hydrochloride and triethylamine is hydrogenated according to the same procedure of Example 2, but using wet (50% H20) Pd/C 10% instead of wet (50% Pt/C 5% to obtain (S)-2-[4-(2-fluorobenzyloxy) benzylamino] propanamide (Ib) in a 70% yield.

EXAMPLE 3 Preparation of (S)-2-[4-(2-fluorobenzyloxy)benzylaminolpropanamide methanesulfonate (ralfinamide methanesulfonate, Id) of high purity degree Ralfinamide (2.8 kg, 9.26 mol), prepared as described in Example 2, is dissolved in iso-propanol (19.5 kg) and kept at 65-70 *C and under stirring under inert atmosphere.

I

0 After treatment with charcoal (150 g) and filtration, the solution is c seeded with pure ralfinamide methanesulfonate and, methanesulfonic acid (900 g, 9.36 mol) is added in 30 minutes, under stirring and at a temperature of 50-55 The suspension is then cooled to 15-20 °C in 2 hours and the stirring is continued for an additional hour. The solid is 00 finally collected by filtration and dried under reduced pressure to give rn 3.59 kg (97.3% yield) of ralfinamide methanesulfonate.

The HPLC purity of the obtained product is 99.8 (area see Example 17A)and the content of C,O-dialkylated (S)-2-[3-(2-fluorobenzyl)-4-(2- N 10 fluorobenzyloxy)-benzylamino]propanamide methanesulfonate is 0.005% by weight (see Example 17B); m.p. 240.6 °C by DSC °C/min).

The enantiomeric purity of ralfinamide methanesulfonate determined with a chiral HPLC column is higher than 99.8 (area see Example 18).

EXAMPLE 4 Preparation of purified 4-(3-fluorobenzyloxy)benzaldehyde (IVa) in ethanol solution To a mixture of 4-hydroxybenzaldehyde (1.52 kg, 12.45 mol), potassium carbonate, (1.72 kg, 12.45 mol), potassium iodide (0.2 kg, 1.20 mol) in ethanol (13.0 kg), 1.8 kg, of 3-fluorobenzyl chloride (1.80 kg, 12.45 mol) are added under stirring, at room temperature.

The mixture is gradually heated to reflux and then kept at that temperature for 6 hours.

The reaction mixture is then allowed to cool to 25 the suspension is filtered and the solid is washed with ethanol (1.0 kg); the ethanol solutions are combined and then concentrated at reduced pressure until a residue of approximately 3.5 kg is obtained.

To this residue, toluene (5.0 kg) and water (1.7 kg) are added, the solvent mixture is stirred vigorously for 30 minutes and, after separation of the aqueous phase, the organic layer is evaporated to N; \el bOuMe\C 900079999\P32AU\PO P7942.AU GH opeci firstC 9/01/09 0dryness under reduced pressure to provide crude 4-(3-

(N

fluorobenzyloxy)benzaldehyde.

To this product dissolved in 2 kg of toluene a seed of 4-(3fluorobenzyloxy)benzaldehyde is added under stirring at 20-25 then n-hexane (3.8 kg) is added in 30 minutes and the mixture is cooled to 00 0 C under stirring.

(N

r c n After 2 hours the solid is filtered and washed with n-hexane (1.3 kg).

After drying, 2.6 kg (90.7% yield) of the desired product are obtained, 0 with a gas-cromathographic purity of 99.9 (area see Example 16A) CN 10 and a 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde content of 0.005% by weight determined by GC (area see Example 16B); m.p.

43.1 °C by DSC 5 °C/min.

EXAMPLE Preparation of 4-(3-fluorobenzyloxy)benzaldehyde (IVa) by phase transfer catalysis A mixture of 3-fluorobenzyl chloride (5 kg, 34.58 mol), 4-hydroxybenzaldehyde (3.9 kg, 31.94 mol), potassium carbonate (4.3 kg, 31.11 mol) and tetradecyl trimethylammonium bromide (0.41 kg, 1.22 mol) in toluene (13.5 kg) is slowly brought to reflux temperature under stirring and under nitrogen atmosphere, and then refluxed for 6 hours.

The solution is concentrated at room pressure and then 3 kg of toluene are added and distilled off. This procedure is repeated once again.

The heterogeneous mixture is then cooled to room temperature and the solid is eliminated by filtration. The residual solvent is eliminated under reduced pressure and then 1.2 kg of toluene are added to the oily residue.

The mixture is stirred at 20-25 °C and seeded with a few grams of pure 4-(3-fluorobenzyloxy) benzaldehyde, and then additioned of n-hexane (9 kg) at this temperature, in 30 minutes.

N:\Melbon\Caeos\Pten\79000-79999\P79432. AU\Spe.\P794 32.AU CH Specl firsc.do 9/01/09 29A After cooling to 0-5 *C and stirring for a further hour at this temperature the solid is collected by filtration and dried under reduced pressure to give 6.5 kg (85% yield, GC purity 99.9 (area see Example 1 6A) and a 3 -(3-fluorobenzyl) (3-fluorobenzyloxy) benzaldehyde content of 0.008% by weight (see Example 16B).

00 M ~5.1 Further purification of 4-(3-fluorobenzyloxvlbenzaldehyde (Na) IND by crystalization C) One kilogram of 4-(3-fluorobenzyloxy)benzaldehyde prepared according to Example 5, is dissolved in 2 kg of diisopropyl ether at reflux under stirring.

N0\Melbounme\Cagee\Paent\79000-79999\P79432.AU\Sp~..\P79432.AU CH sp~ci fie.doc 9/01/09 WO 2007/147491 PCT/EP2007/005105 The solution is cooled to 50-55 OC in 10-15 minutes and seeded with a few grams of pure 4-(3-fluorobenzyloxy)benzaldehyde.

The suspension is cooled to 10-15 'C during 45-60 minutes and stirred for an additional hour.

The precipitate is finally collected by filtration, washed with cool diisopropyl ether (0.2 kg) and dried under reduced pressure to give 0.95 kg of 4-(3fluorobenzyloxy)benzaldehyde with GC purity of 99.9 (area see Example 16A) and a content of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde lower than 0.005% by weight determined by GC (see Example 16B).

5.2 Preparation of 4-(3-fluorobenzyloxy)benzaldehyde (IVal by phase transfer catalysis using 3-fluorobenzyl bromide 4-(3-Fluorobenzyloxy)benzaldehyde is prepared in 86.1% yield with a content of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde of 0.07% by weight determined by GC (see Example 16B) by reacting 4hydroxybenzaldehyde (15.6g) with 3-fluorobenzyl bromide according to the same procedure of Example 5 but using 3-fluorobenzyl bromide instead of 3-fluorobenzyl chloride.

The so obtained 4-(3-fluorobenzyloxy)benzaldehyde is purified according to Example 5.1 to yield the title product in 97.3% yield with a a content of 3- (3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde of 0.07% by weight determined by GC (see Example 16B).

5.3 Preparation of 4-(3-fluorobenzyloxy)benzaldehyde (IVa) by phase transfer catalysis using 3-fluorobenzyl methanesulfonate 4-(3-Fluorobenzyloxy)benzaldehyde is prepared in 97.5% yield with a content of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde of 0.45% by weight, determined by GC (see Example 16B), by reacting 4hydroxybenzaldehyde (15.6g) with 3-fluorobenzyl methanesulfonate instead of 3-fluorobenzyl chloride according to the same procedure of Example This product is further purified according to the procedure of the Example 5.1.

EXAMVIPLE 6 0 Preparation of (S)-2-[4-(3-fluorobenzyloxy)benzylaminolpropanamide 1 (safinamide, la) of high purity degree (one pot reaction) ct c- An autoclave is loaded with, 4-(3-fluorobenzyloxy)benzaldehyde (2.0 kg, 8.69 mol) prepared as in Example 4, and then a solution, prepared apart, of L-alaninamide hydrochloride (1.2 kg, 9.63 mol) and 0 triethylamine (0.97 kg, 9.63 mol) in methanol (7.1 kg) is added thereto.

(N

n The mixture is stirred at 20-25 "C for 1 hour and, after seeding with few grams of (S)-2-[4-(3-fluorobenzyloxy)benzylideneamino]propanamide, 0 stirring is continued for additional 15 minutes. To the stirred c- 10 heterogeneous mixture, methanol (1.8 kg) and, wet (50% H20) Pt/C (Engelhard cod. Escat 22) (0.3 kg) are then added, at 20-25 "C.

The air is purged from the autoclave with nitrogen and then hydrogen is introduced at 5.0 bars.

After 5 hours at 30-35 the mixture is cooled to 15 methanol (4.8 kg) is added and the mixture is heated to 40-45 finally the solid is filtered out and washed with methanol (1.6 kg).

The solvent is eliminated under reduced pressure approximately at "C and then a mixture of ethyl acetate (23.0 kg) and water (18.0 kg) is added to the residue. After stirring for 15 minutes, the aqueous phase is separated and extracted with ethyl acetate (7.0 kg). The collected organic phases are concentrated until a residue of approximately 6.0 kg is obtained. To this residue n-heptane (10.8 kg) is added and the mixture is stirred at 20 "C for about 2 hours. The solid is then collected by filtration and washed with n-heptane.

After drying the solid under reduced pressure, 2.41 kg (91.8% yield) of the title compound are obtained with a HPLC purity of 98.4 (area see Example 17A), and a content of C,O-dibenzylated fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino]propanamide of 0.005% by weight (see Example 17B).

N\Melbourne\Coes\PatenL\79000-7999\P79432.AU\Specia\P79432AU GH *sec1 fr.doc 9101109 6.1 Preparation of (S)-2-14-(3-fluorobenzylogy)benzylamino propanamide (1a) of high Rurity degree by using a Pd catalyst (S)-2-[4-(3-fluorobenzyloxy)benzaldehyde (5 g) in the presence of the corresponding amounts of L-alaninamide hydrochloride and triethylamine is hydrogenated according to the same procedure of 00 Example 6, by using wet (50% H 2 0) Pd/C 10%, instead of wet Pt/C to produce la in a 72% yield.

6.2 Preparation of (S)-2-i4-(3-fluorobenzyloxy)benzylaminoj N- 10 pRopanamide (Ia) of high purity degree by hydrogenation at 1 bar A mixture of (3-fluorobenzyloxy) benzaldehyde, L-alaninamide hydrochloride and triethylamine is hydrogenated according to the same procedure of Example 6, but at 1 bar/H2 instead of 5 bar/H2.

The yield of (3 -fluorobenzyloxy) benzylaminolpropanamide is 90% with a HPLC purity of 98.7 (area see Example 17A) and a content of -2 -[3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino] propanamide of 0.005% by weight determined by HPLC (see Example 1 7B).

6.3 Preparation of (S)-2-[4-(3-fluorobengylogy)benzylaminoI propanamide (Ial of high purity degree (one Rot reaction) by using L-aianinamide base (S)-2-[4-(3-fluorobenzyloxylbenzaldehyde (10g) is reacted according to the same procedure of Example 6, but using L-alaninamide base, instead of its hydrochloride and triethylamine. The yield of fluorobenzyloxy)benzylaminolpropanamide is 92% with a HPLC purity of 99.7 (area see Example 17A) and a content of fluorobenzyl) (3-fluorobenzyloxy) benzylaminolpropanamide lower than 0.005% by weight determined by HPLC (see Example 17B).

N:\Mel boue\Caee,\Patent\79000- 79999\P794 32 .AU\Specto\ P794 32. AU ON .peCi fistd 9/01/09 EXAMPLE 7 Preparation of (S)-2-r4-(3-fluorobenzyloxy)benzylaminolpropanamide methanesulfonate (safinamide methanesulfonate, Ic) of high purity degree Safinamide (2.41 kg, 7.97 mol), prepared as described in Example 6, is 00dissolved in ethyl acetate (56.5 kg) at 65 'C and decoloured with charcoal (100 g).

After filtration, the solution is stirred and seeded with a few grams of safinamide methanesulfonate and, after 15 minutes, methanesulfonic C 10 acid (850 g, 8.84 mol) is added in 30 minutes, at a temperature of 50-55 The suspension is cooled under stirring to 20-25 'C during 2 hours and stirred for an additional hour. The precipitate is finally collected by filtration and dried under reduced pressure to give 2.83 kg (89.1% yield) of safinamide methanesulfonate.

The content of impurity (S)-2-[3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino]propanamide methanesulfonate (IIc) measured by HPLC (see Example 17B) is of 0.005% by weight. The title compound has m.p.

216.8 -C by DSC (5 0 C/min).

The enantiomeric purity, measured with a chiral HPLC column, is over 99.9 (area see Example 19).

1 H-NMR (D20) (Bruker A V300) 6 (ppm, with respect to H20 at 4.7 ppm): 1.43 (3H, d, J 7 Hz, CH 3 2.66 (3H, s, CH 3

SO

3 3.87 (1H, q, J 7 Hz, 3.97 (2H, bs, CH 2 NR); 4.89 (2H, s, CH2OR); 6.88 and 7.23 (4H, AA'XX' aromatic p-disubstituted system,; 6.90 -7.22 (4H, aromatic H) 13 C-NMR (D20) (Bruker AV300) 8 ppm: 15.68 (CH3); 38.27 (CH 3

SO

3

H);

48.99 (CH2NR); 54.81 69.00 (OCH2); 114.15 Jc-F 21 Hz, aromatic CH); 114.76 Jc-F 20 Hz, aromatic CH); 115.38 (aromatic CH); 123.06 JC-F 24 Hz, aromatic CH); 123.24; 130.29 JC-F 6 N:\Melboume\Caeo\Ptent\79OO0-9999\P79432 AU\Specio\P79432AUL GH spect fIrardoc 9/01/09 Hz, aromatic CH); 131.54 (aromatic CH); 138.76 JC-F 7 Hz, aromatic CH); 158.52; 162.89 JO-F 245 Hz, 171.92 (CO).

EXAMPLE 8 Preparation of (S)-2-[4-(3-fluorobenzyloxvlbenzylaminoIpropanamide 00 (safinamide, Ia) of high purity degree, with isolation of the

N-

rnintermediate Schiff base fluorobenzyloxvibenzylideneaminoIpropanamide (VDa) c-I 10 a) (S)-2-14-(3-fluorobengylogy)benzylideneaminolpropanamide (VIa) To a suspension of 4-(3-fluorobenzyloxy)benzaldehyde (60.0 g 0.26 mol), prepared as in the Example 5 and L-alaninamide hydrochloride (35.7 g 0.29 mol) in methanol (280 mL), triethylamine (29.1 g, 0.29 mol) is added at room temperature with stirring under nitrogen atmosphere.

Stirring is maintained for one additional hour.

The solution is then seeded with a few mg of fluorobenzyloxy) benzylideneaminolpropanamide, the temperature is lowered to 5- 10 *C and the stirring continued for 2 hours.

The solid is collected by filtration and washed with methanol at 0 0

C.

After drying it at reduced pressure, 57.3 g (73.2% yield) of the title compound are obtained with m.p. 112.0 *C by DSC (5 *C/min).

1 H-NM)R (DMSO-d 6 (Bruker AV300) 8 (ppm, with respect to TMS at 2.55 ppm; DMSO solvent at 3.35 ppm): 1.31 (3H, d, J 7 Hz, CR3 3.86 (1H, q, J 7 Hz, 5.18 (2H, s, CH2OR); 7.08 and 7.79 (4H, AA".XX' p-disubstituted aromatic system); 7.10-7.50 (4H, m, aromatic H 8.27 (1H, s, CH=NR).

13 C-NMR (DMSO-d 6 (Bruken AV300) 8 (ppm): 20.5 (CR3); 67.6 (CR); 68.4 (OCH2); 114.1 e 114.4 JC-F 21 Hz, aromatic)CH; 114.5 e 114.8 JC-F 21 Hz; aromatic CH; 114.8 (aromatic CH); 123.5 JC-F 2Hz, N: elbumeCauo\Pten\7900-999\P7432AU\p~i\P?432AUCH spect fl-.doc 9/01/09 34A 0 aromatic CH); 129.0 and 129.9 (aromatic CH 130.4 and 130.5 JCF 7 Hz, aromatic CH 139.6 and 139.7 JC-F 6 Hz aromatic c- quaternary C 160.2; 160.5 and 163.8 Jc-F 245 Hz 160.6 (CH=N);174.8 (CO).

00 b) (S)-2-[4-(3-fluorobenzyloxy)benzylaminolpropanamide (la) C An autoclave is loaded with (S)-2-[4-(3-fluorobenzyloxy)benzylidene- I amino]propanamide (16.0 g; 0.053 mol), prepared as described above, and wet (50% H20) Pt/C 5% (1.7 kg: Engelhard Rome, Italy) and ci 10 methanol (90 mL) is added thereto. The autoclave is purged from air with nitrogen and then hydrogen is introduced at 5.0 bars. The reaction is kept at 5.0 bar and at 35 °C for 1 hour. After cooling to room temperature and elimination of the catalyst by filtration, the solvent is distilled off under reduced pressure until a residue of approximately g is obtained. To this residue a mixture of ethyl acetate (150 mL) and (110 mL) is added and the heterogeneous mixture is heated to until two clear phases are obtained. These two phases are separated and the aqueous layer is N\Melboure\Cases\Paten\9000-79999\P79432AU\Specis\P79432AU CH opeci firzt.dc 9/01/09 WO 2007/147491 PCT/EP2007/005105 WO 2 07/1 7491PCTEP20 7/0 10535 extracted with 50 mL of ethyl acetate at 40 9 C. The organic phases are collected and evaporated to dryness. The procedure is repeated twice by adding every time 90 ml of ethyl acetate to make the product anhydrous.

mL of n-heptane are then added slowly and under stirring to the residue. The mixture is then maintained under stirring for 3 hours at 0 C. The solid formed is collected by filtration, washed with n-hetpane mL) and dried under reduced pressure to give 15.2 g (94.8% yield) of safinamide with a HPLC purity of 99.8 (area see Example 17A)and a content of (3-fluorobenzyl) -4-(3-fluorobenzyloxy) benzylaminolpropanamide lower than 0.005% by weight measured by HPLC (see Example 17B).

EXAMPLE 9 Preparation of I-2-r4-(2-fluorobenzyloxvlbenzylaminolpropanamide (ralfinamide. I1b) of high purity degree, with isolation of the intermediate Schiff base (S)-2-[4-(2-fluorobenzvloNX)benzylideneamino1 Rropanamide (VI b) a) (S)-2-[4-12-Fluorobenzlox)benzylideneaminOlprOpanamide (VIb) (S)-2-[4-(2-Fluorobenzyloxy)benzylideneaminolpropanamide is prepared in a 88% yield, m.p. 12100C (capillary), by following the same procedure of Example 8, step a) but using 4-(2-fluorobenzyloxy)benzaldehyde instead of 4-(3-fluorobenzyloxy) benzaldehyde.

1 H-NMR: (CDC1 3 300 MHz, 298K) 8 (ppm, with respect to TMS): 1.46 (3H, d, J= 7.0 Hz, CH 3 3.91 (1H, q, J= 7.0 Hz, OH-GO); 5,17 (2H, s, O-CH2); 7,02 (2H, d, J=8,9 Hz aromatic H ortho to 0-OH 2 7.09 (1H, ddd, JH-F= 9,78 Hz Jarto= 8,55 Hz Jmcta= 1,23 Hz aromatic H ortho to 7,15 (1H, dt, Jorto= 7,35 Hz Jmeta= 1,23 Hz aromatic H para to 7,27-7,40 (1H, m, aromatic H para to OH 2 7,48 (1H, dt, Jorto= JH-F= 7,35 Hz Jmeta= 1,53 Hz aromatic H ortho to OH 2 7,71 (2H, d, J=8,9 Hz aromatic H ortho to CH=N); 8,17 (1H, s, C=N) 13 C-NMR: (CDC 13, 75.4 MHz, 298K) 8 (ppm): 21.4 (CH3); 63.8 (OCH 2 68.4 WO 20071147491 PCT/EP2007/005105 36

(H

2 NC0CH); 115.0 JC-F 22.4 Hz, aromatic CR), 115.5 JC-F= 20.7 Hz, aromatic CR); 123.7 Jc-F= 14.4 Hz, quaternary aromatic 124.5 (bd, aromatic OH 129.0 (quaternary aromatic 129.8 (bd, aromatic CH); 130.1 (bd, 2 aromatic CH); 160.5 JC-F= 246.4 Hz, quaternary aromatic 161.1 (aromatic 161.1 176.9 (CONH2) b) (S)-2-r4-(2-Fluorobenzvloxv)benzylaminOlI~ropanamide UJb) -Fluorobenzyloxy) benzylaminolpropanamide is prepared in a 93% yield from 4- (2 -fluorobenzyloxy) benzylideneamino] propanamide by following the same procedure of Example 8, step The content of (2-fluorobenzyl) (2-fluorobenzyloxy) -benzylaminolpropanamide is 0.02% by weight determined by HPLC (see Example 17B3).

EXAMPLE Preparation of (S)-2-r3-13-fluorobenzl-4-(3-fluorobenzoxV)benzylaminOIKpRoanamide methanesulfonate (Ile) a) 3-(3-Fluorobenzyl)-4-(3-fluorobenzyloxv)benzalde hyde (Va In a 4 L round bottomed flask kept under nitrogen atmosphere, 4-hydroxybenzaldehyde (400 g, 3.28 mol), potassium carbonate (453 g, 3.28 mol), toluene (2 L) and 3-fluorobenzylchloride (1400 g, 9.68 mol) are added in sequence and the mixture is refluxed under stirring for 5 days. At this point a GC analysis reveals that the reaction mixture contains 4-(3fluorobenzyloxy)benzaldehyde and 3- (3-fluorobenzyl) -4 fluorobenzyloxy)benzaldehyde in a ratio of 91.4 :8.6 (area/area, see Example 16A).

The reaction mixture is cooled to room temperature and then 2 L of water are added under stirring. The organic phase is separated and the solvent is distilled under reduced pressure (20 mmHg) at 35 '0 until no more solvent passes over. The pressure is then lowered to 3 mmHg and the external temperature is raised up to 300 0 C and the fraction that distils beween 255 'C and 265 (40.6 is collected.

A GO analysis shows a area/area ratio of C,0-dibenzylated derivative (Va) of the tile compound vs. the monoalkylated one of 99.6:0.4.

WO 2007/147491 PCT/FP2007005105 37 (area/area, see Example 16A).

1H-NMR (CDCb1) (Bruker AV300) 6 (ppm, with respect to TMS): 4.05 (2H, s, CH2); 5.13 (2H, s, OCH2); 6.85-7.40 (9H, m, aromatic 7.73-7.79 (2H, m, aromatic H ortho to 9.88 CHO).

13 C-NMR (CDC13) (Bruker AV300) 8 (ppm): 36.1 (CH2); 69.4 (CH20); 111.4 (aromatic CH );112.9 and 113.2 Jc-F= 20 Hz, aromatic CH 113.9 and 114.2 JC-F 22 Hz, aromatic CH 114.9 and 115.0 JC-F 21 Hz, aromatic CH 115.7 e 115.9 Jc-F= 25 Hz aromatic CH 122.6 Jc-F= 3 Hz, aromatic CH 124.4 Jc-F 3 Hz, aromatic CH 129.6 and 129.8 (d, Jc-F 8 Hz, aromatic CH); JC-F 7 Hz, quaternary aromatic 129.9 (C quaternary aromatic 130.0 quaternary aromatic 130.1 and 130.2 Jc-F 7Hz, CH aromatic); 131.2 aromatic CH); 131.5 aromatic CH); 138.3 Jc-F 7 Hz, quaternary aromatic 142.3 JC-F 7 Hz, quaternary aromatic 161.0, 161.2 and 164.4 JC-F 240, 2 C-F overlapping); 190.8 (CHO).

b) (S)-2-[3-13-Fluorobenzvl)-4-(3-fluorobenzyloxy)benzylaminolpropanamide (Ha) To 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde (35.6 g, 0.105 mol) in a 500 mL flask, a solution previously prepared by cautiously adding under stirring triethylamine (12 g, 0.119 mol) to a 170 mL methanol solution of L-alaninamide hydrochloride (14.8 g, 0.119 mol), is added at room temperature.

This reaction mixture is stirred for 1 hour at room temperature and then it is transferred to a 1.8 L autoclave and additioned of 3.4 g of wet (50% H 2 0) Pt/C The air is purged from the autoclave with nitrogen and then hydrogen is introduced at 5.0 bar.

The reaction is performed at a temperature of 35 °C for 3-5 hours.

After cooling to room temperature and eliminating the catalyst by filtration, the solvent is distilled off under reduced pressure until a residue of approximately 65 g is obtained. To this residue a mixture of ethylacetate WO 2007/147491 PCT/EP2007/005105 38 (340 mL) and water (250 mL) is added and the heterogeneous mixture is warmed to 40 °C and kept at this temperature without stirring, until two clear phases are obtained. The two phases are separated and the organic one is distilled under reduced pressure, until a residue of approximately g is obtained.

This residue is dissolved in 220 mL of ethyl acetate and the solvent distilled off under reduced pressure with an external temperature of 40 This operation is repeated twice and the title compound is obtained as solid residue.

c) (S)-2-[3-(3-Fluorobenzyl)-4-(3-fluorobenzyloxy)benzylaminolpropanamide methanesulfonate (Hec) In a 2 L glass reactor 42.4 g (0.103 mol) of (S)-3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)-benzylamino]propanamide base are dissolved in 950 mL of ethyl acetate.

The solution is heated under stirring at 50-55 °C and kept at this temperature for one hour. To this solution, 14.5 g (0.15 mol) of methanesulfonic acid are added in 20 minutes, and the temperature is lowered to 20 °C in 90 minutes. After 30 minutes the solid is collected by filtration, dried at 50 °C under reduced pressure and then crystallized from methanol (methanol product 1:5 by weight) to obtain 25.1 g of fluorobenzyl)-4-(3-fluorobenzyloxy)-benzylamino]propanamide methanesulfonate, m.p. 181°C (capillary).

1 H-NMR (DMSO-d 6 (Bruker AV300) 8 (ppm, with respect to TMS): 1.44 (3H, d, J 7Hz, CH 3 2,35 (3H, s, CH 3

SO

3 3,81 (1H, q, J 7 Hz, 3.99 (2H, bs, CH2 benzylic); 4.02 (2H, AB system, CH2N-); 5.17 (2H, s, 6.98-7.63 (11H, m, aromatic 7.62 and 7.75 (2H, bs, NH 2 amide 9.02 (2H, broad, NH2+).

13 C-NMR (DMSO-d 6 (Bruker AV300) 8 (ppm): 15.9 (CH 3 35.5 (CH 2 39.7 (CHaSOaH); 48.1 (CH2NR); 54.4(CH); 68.4(OCH2); 112.2 (aromatic CH); 112.7 Jc-F 22Hz, aromatic CH); 113.8 JC-F 22Hz, aromatic CH); 114.5 Jc-F 22 Hz, aromatic CH); 115.2 JC-F 22Hz, aromatic CH); 0 123.2 (aromatic CH); 123.8; 124.6 (aromatic CH); 128.7 and 130.0 (d, JHc-F 6Hz, aromatic CH); 130.04 (aromatic CH); 130.3 JC-F 6Hz, aromatic CH); 132.6 (aromatic CH); 139.8 JC-F 7Hz); 143.4 JC-F 7 Hz); 158.1, 160.5 and 163.7 JC-F 240, 160.6 and 163.8 (d, JC-F 240, 170.5 (CON).

00 M, A sample (90 mg) of (S)-2-[3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)- ,q benzylamino]propanamide (IIa) is isolated also by preparative HPLC 0from a 200 g of safinamide methanesulfonate (Ic) prepared according to CN 10 J. Med. Chem., 1998, 41, 579, method A, that contains it, as methanesulfonate (IIc), in 0.12% by weight.

The separation is performed, in two stages (Stage 1 and Stage 2), according to the following scheme: N:\aelooume\Caoes\\Patent\7000-9999\P79432.AU GH apl fire.dc 9/01/09 39A Isolation of Ila by preparative HPLC of safinamide methanesulfonate (1c) contaminated by 0. 12% by weight of hIc Ic impure for lic I Stage 1 47 47 Fraction I Fraction 2 Safinamide Safinamide 47 47 47 47 Fraction 3 Raction 4

I

tm fri t y IOgncsolvent removal IHa/FFA I~ Stage 2 4 1- Fraction I Fraction 2 Fraction 3 Fraction 4 Fraction Waste Organic solvent removal Crystallization at 4*C Filtration 4I Filtrate HaS Sl id N:\meiooue\Coes\patenl\7900O-79999\779432.AU\SpeCl\79432.AU GH PeCl 717.t.doc 9/01/09 WO 2007/147491 PCT/EP2007/005105 Stage 1 The scope of the first stage is to isolate a crude product enriched in IIa/TFA (Trifluoroacetic acid).

Preparative HPLC conditions are reported below: Preparative HPLC conditions: Instrument: Waters Delta Prep 4000 (reciprocating pump, gradient controller with low pressure mixer) Radial Compression Module Prep LC Base (Waters) Jasco 7125 UV-Variable detector, o.p. 0.2 mm Merk D2000 printer-plotter Column: Delta Pak C18, 15pm, 40x100mm (Waters) Eluent A: 70/30, Water/Acetonitrile 0.1% TFA Eluent B: 30/70, Water/Acetonitrile 0.1% TFA Flow rate: 27.0 ml/min Gradient: 40 min, isocratic 100% A, then to 100% B in 1 minute Detection: UV 227 nm Injection: 5 g in 50 ml of Water (by pump inlet line D) Stage 2 This stage is needed to eliminate TFA from IIa/TFA and to further purify IIa.

IIa/TFA is chromatographed using the preparative HPLC conditions given below.

The fraction 4 and 5 are combined together and evaporated at 40 °C under vacuum until complete removal of acetonitrile. The residual water solution is kept in a refrigerator at 4 The insoluble is isolated by filtration and dried under vacuum at room temperature to provide IIa (90 mg; HPLC purity 100%).

Preparative HPLC conditions: Instrument: Waters Delta Prep 4000 (reciprocating pump, gradient WO 2007/147491 PCT/EP2007/005105 41 controller with low pressure mixer) Jasco 7125 UV-Variable detector, o.p. 0.2 mm Merk D2000 printer-plotter Column: Symmetry C 18, 7 jim, 20x250mmn (Waters) Eluent A: 70/30, Water/ Acetonitrile Eluent B: 30 /70, Water/ Ace tonitrile Flow rate: 15.0 mi/min Gradient: 20 min, isocratic 100% A, then to 100% B in minutes Detection: UV 227 nm Injection: 50 ml of impurity "IRa/TFA" solution (by pump inlet line D) EXAMvPLEl11 Preparation of (S)-2-j3-12-fluorobenzvll-4-(2-fluorobenzylogv)benzvlaminolpropanamide methanesulfonate (Ild) a) 3-(2-Fluorobenzvl)-4-(2-fluorobenzvloxyI benzaldehyde (VI,) 3- (2 -Fluorobenzyl) -fluorobenzyloxy)benzaldehyde is prepared by following the same procedure of Example 10, step a) in a 1:10 scale, but using 2-fluorobenzyl chloride instead of 3-fluorobenzyl chloride. The molar yield is 3% with a 98.1 purity determined by GC analysis (area see Example 16A). The product has m. p. 7 1 C (capillary).

'H-NMR: (CDCl 3 300 MHz, 298K) 5 (ppm, with respect to TMS): 4.06 (2H, s, CH 2 5.23 (2H, s, OCH 2 6.95-7.40 (9H, m, aromatic 7.67 (1H, bd, J= 0.9 Hz, aromatic H ortho to C=O and CR 2 7.76 (1H, dd, J 1 2.1 Hz, J 2 8.3 Hz, aromatic H ortho to C=O and aromatic CH); 9.84 (1 H, s, CH0).

3 C-NMR: (CDC 1 3 75.4 MHz, 298K) 8 (ppm): 29.2 (CR 2 64.1 (OCH 2 111.4 (aromatic CR); 115.4 JC-F= 22.0 Hz, aromatic CH), 115.5 JC-F= 21.1 Hz, aromatic CH); 123.3 JC-F= 14.2 Hz, quaternary aromatic 124.1 (d, JC-F= 2.6 Hz, aromatic CHR); 124.5 JC-F= 3.2 Hz, aromatic CH); 126.6 (d, WO 2007/147491 PCT/EP2007/005105 42 JC-F= 15.5 Hz, quaternary aromatic 128.2 JC-F= 8.1 Hz, aromatic CH); 129.6 JC-F= 6.2 Hz, aromatic CH); 129.6 (quaternary aromatic 130.0 (quaternary aromatic 130.2 JC-F= 8.3 Hz, aromatic OH); 131.1 (aromatic CH); 131.3 JC-F= 4.1 Hz, aromatic OH); 131.8 (aromatic CH); 160.5 Jc-F= 246.8 Hz, quaternary aromatic 161.2 Jc-F= 245.1 Hz, quaternary aromatic 161.3 (quaternary aromatic 19 1.1 (CR0).

b) (S)-2-[3-(2-Fluorobenzyl)-4-12-fluorobenzylogv)benzylaminolyrovanamide tu1b) 13-(2-Fluorobenzyl)-4- (2 -fluorobenzyloxy)benzylamino] -propanamide is prepared by following the same procdure of Example 10, step b) by using 3- (2-fluorobenzyl) -4 -fluorobenzyloxy)benzaldehyde instead of 3- (3fluorobenzyl) -fluorobenzyloxy) benzaldehyde. The yield is 83%; m. p.

1610C (capillary).

1 H-NMR: (CDC13, 300 MHz, 298K) 6 (ppm, with respect to TMS): 1.32 (3H, d, J= 6.7 Hz, CH 3 1.97 (1H, bs, NH); 3.22 (1H, q, J= 6.7 Hz, CH-CO); 3.67 (2H, ABq, J= 12.8 Hz, diastereotopic H of NCH 2 4.03 (2H, s, OH 2 5.12 (2H, s, OCH2); 5.98 (1H, bs, NH2); 6.89 (1H, d, Jorto= 8.3 Hz, aromatic H ortho to CH 2 NH and aromatic OH); 6.95-7.40 (10H, m, aromatic H).

1 3 C-NMR: (CDC13, 75.4 MHz, 298K) 6 (ppm): 19.6 (CR3); 29.2 (CR2); 52.0 (NHCH2); 57.7 (H 2 NC0CH); 63.8 (OCH2); 111.7 (aromatic CH); 115.2 Jc- F= 21.9 Hz, aromatic CH), 115.3 Jc.F= 21.3 Hz, aromatic CH); 124.0 (d, Jc-F= 3.5 Hz, aromatic CH); 124.3 JC-F 2.9 Hz, aromatic OH); 124.3 (d, JC-F= 14.4 Hz, quaternary aromatic 127.5 (aromatic CR); 127.6 JC-F= 15.0 Hz, quaternary aromatic 127.8 JC-F= 7.5 Hz, aromatic OH); 128.8 (quaternary aromatic 129.0-130.0 (in, 2 aromatic CH); 130.5 (aromatic CH); 131.3 JC-F= 4.6 Hz, aromatic CH); 131.8 (quaternary aromatic 155.6 (quaternary aromatic 160.4 J 0 245.8 Hz, quaternary aromatic 161.2 JC-F= 244.6 Hz, quaternary aromatic 178.2 (CONH 2 c) (S)-2-i3-(2-fluorobenzyl)-4-(2-fluorobenzylogy)-.

benzylaminolpropanamide methanesulfonate (1141 (2 -fluorobenzyl) (2 -fluorobenzyloxy) benzylamino] propanamide methanesulfonate is prepared by following the same procedure of 00 Example 10, step c) but using (S)-2-[3-(2-fluorobenzyl)-4-(2rn fluorobenzyloxy)benzylaminolpropanamide as the starting material. The yield is 89%; m.p. 190 *C (capillary).

N- 10 'H-NMR: (DMSO-d6, 300 MHz, 298K) 8 (ppm, with respect to TMS): 1.42 (3H, d, J= 6.8 Hz, CH 3 CH); 2.33 (3H, s, CH 3

SO

3 3.50-4.20 (5H, m, CH- CO, CR2, diastereotopic H of NCR 2 5.19 (2H, s, OCH2); 6.95-8.00 (1l1R, m, aromatic 9.02 (2H, bs, NH2+).

3 C-NMR: (DMSO-d 6 75.4 MHz, 298K) 8 (ppm): 16.5 (CR 3 28.8 (CH2); 48.6 (NHCH2); 54.9 (H2NCOCH); 64.3 (OCH2); 112.8 (aromatic CH); 115.0-117.0 (2 aromatic CR); 124.2 JC-F= 14.4 Hz, quaternary aromatic 124.4 (quaternary aromatic 124.8 (aromatic CR); 125.0 (aromatic CR); 127.3 JC-F= 16.1 Hz, quaternary aromatic 128.6 (quaternary aromatic 128.8 (aromatic CR); 129.0-133.0 (in, aromatic CR); 156.9 (quaternary aromatic 160.8 Jc-F= 245.2 Hz, quaternary aromatic 160.9 JC-F= 243.5 Hz, quaternary aromatic 171.1 (CONH2).

EXAMPLE 12 Preparation of (S)-2-4-3-fluorobenzyloxylbenzylamnnlproanamide (safinamidel methanesulfonate (1c) from 43 fluorobenzylogy)benzaldehyde (IVa) contaminated by 1% by weight of impurity 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxylbenzaldehyde (Va) To 4-(3-fluorobenzyloxy)benzaldehyde (10 g; GC purity 98.8, area%) 1% of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde is added NA\Melbume~\C.e\Patent\79O0O-79999\P79432.AU\pcC15\P?9432AU GH .peci firs.dO 9/01/09 and the mixture is converted into fluorobenzyloxy)benzylaminojpropanamide safinamide base by following the same procedure of Example 6. The yield is 84% with a content of impurity (Ila) of 0.84% (see Example 17B) by weight.

The free base (3 -fluorobenzyloxy)benzylaminolpropanamide (Ia) 00 is converted into the corresponding methanesuiphonate by following the

(N

rn same Iprocedure of Example 7 to provide the methane sulphonate (Ic) in IND 98% yield with a content of impurity (S)-2-[3-(3-fluorobenzyl)-4-(3- 0 fluorobenzyloxy)benzylamino]propanamide methanesulfonate (IIc) of ci 10 0.62% by weight determined by HPLC (see Example 1713).

EXAMPLE 13 Crvstalization of safinamide methanesulfonate 00c contaminated by impurity (lic) The safinamide methanesulfonate contaminated by fluorobenzyl) -4-(3-fluorobenzyloxy)benzylaminolpropanamide methanesulfonate (JIc) of 0.62% by weight determined by HPLC (see Example 1B, obtained according to Example 12, is crystallized by using five different(s) solvent systems by dissolving at reflux temperature and cooling at room temperature.

The result are reported in the following Table N\ M.Ibou.,\Case\Pate.,tA'9000-'9999\P'9432.AU\Speci.\P79432.AU CH speci firet.do 9/01/09 44A TABLE TEST No. SOLVENT SYSTEM AND w/w of THc Molar Yield AMOUNT (mL/g) in Ic after crystallization 11) 13a 2-PrOH/MeOH 2:1, 45 0.28 44.9 13b EtOAc/MeOH 4:1, 50 0.15 29.6 13c EtOR, 10 0.30 73.2 13d Acetofl/H20 -27:1, 0.08 20.6 40.5 13e Acetonitrile /H20 60: 1, 0.09 69.3 30.5 the is evaluated according to Example 17B.

EXAMPLE 14 N:\Melboure\Cseo\Paent\79000.79g99\P79432.AU\SpeCia\P79432.AU Gil apeci firs.dwo 9/01/09 WO 2007/147491 PCT/EP2007/005105 Preparation of (S)-2-[4-(3-fluorobenzyloxv)benzylaminolpropanamide (safinamide, la) methanesulfonate (Ic) according to the methods described in the prior art 14.1 Preparation of 4-(3-fluorobenzvloxv)benzaldehyde (IVa) 14.1.a) Procedure of Example la of US 6,335,354 B2 4-(3-Fluorobenzyloxy)benzaldehyde (IVa) is prepared by the procedure described in Example la of US 6,335,354 B2.

Accordingly, a mixture of 3-fluorobenzyl chloride (2.86 g,19.80 mmol) 4hydroxybenzaldehyde (3.03 g, 24.80 mmol), K 2 COa (10.30 g, 74.50 mmol Nal (137.1 mg, 0.91 mmol), and ethanol, (40 mL) is heated to reflux in minutes and kept at reflux temperature for 4 hours and 15 minutes.

After working up the reaction mixture, 4-(3-fluorobenzyloxy)benzaldehyde, is isolated as a yellow oil in 95% yield.

The product has GC purity of 97.6 (area see Example 16A) and a content of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde (Va) of 0.14% by weight determined by GC (see Example 16B) 14.1.b) Procedure ofJ. Agric. Food Chem, 27, 4, 1979 4-(3-Fluorobenzyloxy)benzaldehyde (IVa) is prepared by the procedure reported in J. Agric. Food Chem, 27, 4, 1979.

Accordingly, 3-fluorobenzyl chloride (14.5g, 100 mmol) is added under stirring and under nitrogen atmosphere to a solution of 4hydroxybenzaldehyde (12.2g, 100 mmol) and of NaOH (4.0g, 100 mmol) in ethanol (100 mL).

The mixture is gradually heated in 25 minutes to reflux and stirred at reflux temperature for 6 hours and 20 minutes. The reaction mixture is filtrated and then concentrated at reduced pressure to obtain 4-(3-fluorobenzyloxy)benzaldehyde (23.43 g) as a yellow solid residue.

Dichloromethane (250mL) is added to the residue, the insoluble is filtered and the resulting solution is concentrated under reduced pressure to provide 4-(3-fluorobenzyloxy)benzaldehyde as a yellow solid, in 80.4% yield.

The product has GC purity of 91.6 (area see Example 16A) and a content of 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde (Va) of 0.13% by weight determined by GC (see Example 16B).

Ct M 14.2 Preparation of (S)-2-[4-13-fluorobenzylox)benzylamino propanamide (Ia) and its methanesulfonate salt (Ic) 14.2.a) Procedure of J. Med. Chem., 1998, 41, 579, method A 00 (S)-2-[4-(3-Fluorobenzyloxy)benzylamino]propanamide (Ia) is prepared c by reacting 4-(3-fluorobenzyloxy)benzaldehyde (10 mmol), prepared as N described in Example 14.1.a., and L-alaninamide hydrochloride (1.37 g, 11immol) followed by reduction with NaBH 3 CN(0.50 g, 8 mmol). After 1 10 working up the reaction mixture and purification by flashchromatography, (S)-2(4-(3-fluorobenzyloxy)benzylamino]propanamide is isolated as white solid in 68.7% yield. The product has HPLC purity of 96.2 (area see Example 17A) and a content of fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino]propanamide (IIa) of 0.15% by weight (see Example 17B).

A mixture of (S)-2[4-(3-fluorobenzyloxy)benzylamino] propanamide (1.50 g, 4.96 mmol) and ethyl acetate (40.2 mL) is heated to 50 0 C until a clear solution is obtained. Methanesulfonic acid (0.53 g, 5.51 mmol) is added under stirring in 15 minutes to the solution and the resulting heterogeneous mixture is cooled under stirring to 20 *C in 90 minutes.

After 30 minutes at 20 'C the solid is collected by filtration, washed with ethyl acetate (6 mL) and dried at 50 'C at reduced pressure for hrs to provide (S)-2[4-(3-fluorobenzyloxy)benzylaminoJpropanamide methanesulfonate (Ic) as a white solid in a 96.1% yield. The product has HPLC purity 98.6 (area see Example 17A) and a content of (3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino]propanamide methanesulfonate (IIc) of 0.10% by weight determined by HPLC (see Example 17B).

14.2.b) Procedure of J. Med. Chem., 1998, 41, 579, method A (S)-2-[4-(3-Fluorobenzyloxy)benzylamino]propanamide (Ia) is prepared according to example 14.2.a from 4-(3-fluorobenzyloxy)benzaldehyde N:\MelboUme\Cege\P.aent\79000-79999\P79432 AU\SPecIe\P79432AU CH spel fIr.tdoc 9/01/09 mmol), prepared as described in example 14. and L-alaninamide hydrochloride (1.37 g, 1 immol) followed by reduction with NaBH 3 CN(0.50 g, 8 mmol).

-2(4 -(3-fluorobenzyloxy) benzylamino] propanamide is obtained as white solid in 66.5% yield. The product has HPLC purity of 88.5 (area 00 see Example 17A) and a content of (S)-2-[3-(3-fluorobenzyl)-4-(3-

N-

fluorobenzyloxy)benzylaminolpropanamide (Iha) of 0.064% by weight (idetermined by HPLC (see Example 17B). fluorobenzyloxy)benzylaminolpropanamide (Ia) is converted into the Cl 10 corresponding methanesulfonate (Ic) in a 88.9% yield by treatment with methanesulfonic acid according to Example 14.2.a. The product has a HPLC purity of 97.7 (area see Example 17A) and a content of (3 -fluorobenzyl) (3-fluorobenzyloxy) benzylamino] propanamide methanesulfonate (IIc) of 0.05% by weight determined by HPLC (see Example 17B).

EXAMPLE Preparation of (S)-2-[4-(2-fluorobenzyloxvlbenzylaminOlpropanamide (ralfinamide, Iib) methanesulfonate (Id) according to the methods described in the Rrior art 15.1 Preparation of 4-(2-fluorobenzyloxv)benzaldehyde (IVb) 15.1.a) Procedure of Example la of US 6,335,354 B2 4-(2-fluorobenzyloxy)benzaldehyde (IVb) is prepared according to the Example 14.1.a) from 2-fluorobenzyl chloride (14.3 g, 98 mmol), 4hydroxybenzaldehyde (15.1 g, 123 mmol), K 2 C0 3 (51 g, 369 mmol), Nal (500 mg, 3.3 mmol.) ethanol, 75 mL.

The mixture is kept at reflux for 12 hrs. After working up the reaction mixture, 4-(2-fluorobenzyloxy)benzaldehyde is obtained in 75% yield as a yellow oil. The product has GC purity of 92.1 (area see Example 16A) and a content of 3-(2-fluorobenzyl)4-(2- N:\elbumecaoe~pten\7900-999\P7432AU\peCS\P943.AUGil speci fir.t.8oc 9/01/09 fluorobenzyloxy)benzaldehyde of 0.25% by weight determined by GC (see Example 16B).

15.1.b) Procedure of J. Agric. Food Chem, 27, 4, 1979 4-(2-fluorobenzyloxy)benzaldehyde (IVb) is prepared according to Example 14.1.b from 2-fluorobenzyl chloride (18.0 g, 123 mmol), 4hydroxy-benzaldehyde (15.3 g, 125 mmol), NaOH (5.0 g, 12 mmol) and IDethanol (125 mL).

The mixture is heated in 25 minutes to reflux and kept at reflux N 10 temperature under stirring for 12 hours.

After working up the reaction mixture according to Example 14.1.b 4-(2fluorobenzyloxy)benzaldehyde is obtained as a yellow solid, in 90.0% yield. The product has GC purity of 90.4 (area see Example 16A) and a content of 3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde (Vb) of 0.14% by weight determined by G.C. (see Example 16B).

15.2 Preparation of (S)-2-14-(2-fluorobenzloxy)benzvlamino propanamide (Ib) and its methanesulfonate salt (Id) 15.2.a) Procedure of J. Med. Chem, 1998, 41, 579, method A (S)-2-[4-(2-fluorobenzyloxy)benzylamino]propanamide (Ib) is prepared following the procedure of Example 14.2.a by using 4-(2fluorobenzyloxy)benzaldehyde (10 mmol, prepared as in Example 15.1a) instead of 4-(3-fluorobenzyloxy)benzaldehyde.

(S)-2[4-(2-fluorobenzyloxy)benzalamino]propanamide is obtained in 67.3% yield as a white solid. The product has a HPLC purity of 86.7 (area see Example 17A) and a content of (S)-2-[3-(2-fluorobenzyl)-4- (2-fluorobenzyloxy)benzylamino]propanamide (IIb) of 0.22% by weight determined by HPLC (see Example 17B).

A mixture of (S)-2[4-(2-fluorobenzyloxy)benzylamino] propanamide (1.50 g, 4.96 mmol) and propan-2-ol (10.5 mL) is heated to 50 'C and kept at this temperature until a clear solution is obtained. Methanesulfonic acid, (0.48 g, 5.01 mmol) is added under stirring in 15 minutes.

NT\Melbourne\Cases\Patent\79000-79999\P79432.AU\Spci.\P7943 .U GH OpeC- tiLr.dOC 9/01109 The heterogeneous mixture is then cooled under stirring to 20 'C in 2 hours. After 1 hour at 20 *C the solid is collected by filtration, dried at n reduced pressure to provide -2 (2-fluorobenzyloxy)benzylamino] propanamide methanesulfonate as white solid in 89.1% yield. The product has a HPLC purity of 96.9 (area see Example 17A) and a 00 content of [3-(2-fluorobenzyl)

(N

fluorobenzyloxy) benzylamino] propanamide methanesulfonate (Id) of 0. 14% by weight determined by HPLC (see Example 17B).

ci 10 15.2.b) Procedure of J. Med. Chem. 1998, 41, 579, Method A (2 -Fluorobenzyloxy) benzylaminolpropanamide (Tb) is prepared according to Example 14.2.b by using -2 fluorobenzyloxy)benzaldehyde (10 mmol, prepared according to Example L.b) instead of 4-(3-fluorobenzyloxy)benzaldehyde.

(S)-2-[4-(2-Fluorobenzyloxy)benzylaminolpropanamide is obtained as a white solid in 58.8% yield. The product has a HPLC purity 83.8 (area see Example 17A) and a content of (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzylaminojpropanamide (Ilb) of 0. 15% by weight determined by HPLC (see Example 17B).

(2 -fluorobenzyloxy) benzylamino]propanamide (Tb) is converted into the corresponding methanesulfonate (Id) in a 89.4% yield as a white solid. The product has a HPLC purity of 95.2 (area see Example 17A) and a content of (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy) benzylamino] propanamide methanesulfonate of 0.11% by weight determined by HPLC (see Example 17B).

EXAMPLE 16A GC determination of 4-(3-fluorobenzylogylbenzaldehyde and 4-(2fluorobenzvloxylbenzaldehyde purity.

Test preparation Dissolve about 100 mg of the sample in 10 mL of methylene chloride.

N:\Melbourn.\Cas.\Patent\79000-79999\P79432.AU\SpeCia\P79432.AU GH speci first~oc 9/01/09 Chromatographic conditions The chromatographic procedure is carried out by using: a fused silica capillary column 60 m long and 0.32 mm internal diameter. RTX 35 (35% Diphenyl- 65% Dimethyl polysiloxane) Film thickness= 0.25 pm; helium as carrier gas at a pressure of 150 kPa; a split flow of 25 ml/min; injector temp. 290 °C; detector (FID) temp. 290 °C; with the following temperature program: Time (min) Temperature (IC) Rate (°C/min) Comment 150 isothermal 5-11 150-.240 15 linear gradient 11-19 240 isothermal 19-20.7 240-+290 30 linear gradient 20.7-40 290 isothermal Procedure Inject 1 pl of the Test Preparation. Record the chromatogram and calculate the product purity by area percent calculation.

Impurities identification 4-(3-fluorobenzyloxy)benzaldehyde (IVa): Retention times: 4-(3-fluorobenzyloxy)benzaldehyde retention time is about 17.

4-Hydroxybenzaldehyde relative retention time is about 0.52.

4-(2-fluorobenzyloxy)benzaldehyde relative retention time is about 0.98.

4-(4-fluorobenzyloxy)benzaldehyde relative retention time is about 1.01.

4-Benzyloxybenzaldehyde relative retention time is about 1.02.

3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde relative retention time is about 1.78.

N:\elbourne\Case\Patent\19000-7999\P79432.AU\Spci\P79432.AU ON 0sed firds.doc 9/01/09 4- (2 -fluorobenzyloxy) benzaldehyde (fIb): Retention times: 4-(2-fluorobenzyloxy)benzaldehyde retention time is about 17.

4-Hydroxybenzaldehyde relative retention time is about 0.53.

4-(3-fluorobenzyloxy)benzaldehyde relative retention time is about 1.02.

00 4-(4-fluiorobenzyloxy)benzaldehyde relative retention time is about 1.03.

(N

4-Benzyloxybenzaldehyde relative retention time is about 1.04.

ID3- (2 -fluorobenzyl) (2 -fluorobenzyloxy) benzaldehyde relative retention 0 time is about 1. 81.

N \elou e\aoe\Ptet\900-799\P942.U\SeCB\7932AU CH spect f~OLd 9/01/09 WO 2007/147491 PCT/EP20071005105 51 EXAMPLE 16B GC determination of the content of 3-(2-fluorobenzyll-4fluqrobenzyloxv)benzaldehyde (Vb) in 4-(2-fluorobengyloxv) benzaldehyde (IVb) and of 3-(3-fluorobenzyl)-4-(3-fluorobenzvloxvl benzaldehyde (Va) in 4-(3-fluorobenzyloxvlbenzaldehyde (Wa) The known related substance taken into consideration for 4-(2fluorobenzyloxy)benzaldehyde is the 3- (2 -fluorobenzyl) (2fluorobenzyloxy)benzaldehyde and for 4-(3-fluorobenzyloxy)benzaldehyde is the 3- (3-fluorobenzyl) (3-fluorobenzyloxy) benzaldehyde. The determination is carried out according to the following conditions: Internal standard solution Prepare a 3,4,5-trimethoxybenzaldehyde solution with concentration mg/mi in methylene chloride (IS).

Reference solution for the 3- (2 -fluorobenzvl)-4- (2 -fluorobenzvloxv) benzaldehyde determination in the 4-(2-fluorobenzvloxv)benzaldehyde: Accurately weigh about 20 mg of 3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzaldehyde reference standard and 20 mg of 4-(2fluorobenzyloxy)benzaldehyde reference standard in a 20 mL volumetric flask dissolve and dilute to volume with diluent transfer 500 1-11 of this solution in a 5 mL volumetric: flask, add 500 VL of IS solution and dilute to volume with diluent to obtain a solution containing 3-(2-fluorobenzyl)-4-(2fluorobenzyloxy) benzaldehyde and 4- (2 -fluorobenzyloxy)benzaldehyde at about 100 pg/ mL corresponding to about 0. 10%) Reference solution for the 3 -(3-fluorobengyl)-4- (3 -fluorobenylov') benzaldehyde determination in the 4-(3-fluorobenzvloxvY)benzaldehyde Accurately weigh about 20 mg of 3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzaldehyde reference standard and 20 mg of 4-(3fluorobenzyloxy)benzaldehyde reference standard in a 20 mL volumetric flask dissolve and dilute to volume with diluent transfer 500 1 iL of this WO 2007/147491 PCT/EP2007/005105 52 solution in a 5 mL volumetric flask, add 500 pL of IS solution and dilute to volume with diluent to obtain a solution containing 3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzaldehyde and 4-(3-fluorobenzyloxy)benzaldehyde at about 100 ig/mL corresponding to about 0.10%) Test solution: Accurately weigh about 500 mg of test product in a 5 mL volumetric flask, add 500 pL of IS solution dissolve and dilute to volume with diluent to obtain a solution having known concentration of about 100 mg/mL.

Chromatographic conditions: The chromatographic procedure is carried out by using: -Column a fused silica capillary column RTX 35 35% Dimethyl polysiloxane 60 m long 0.32 mm I.D. film thickness 0.25 m Carrier helium) at pressure of 150 kPa; Split flow 25 mL/min; Injector temp. 290°C; Detector (FID) temp. 2900C; Temperature program 0-5 min isothermal at 150C 5-11 min linear from 150°C to 240°C at a rate of 15°C/min 11-19 min isothermal at 240 0 C 19-21 min linear from 240°C to 2900C at a rate of 30°C/min 21-40 min isothermal at 290°C; diluent methylene chloride injection volume 1 pL.

Procedure: Inject blank (diluent), reference solution, test solution and record the chromatograms.

In the reference chromatogram verify that: 4-(2-Fluorobenzyloxy)benzaldehyde retention time is about 18 min; 3-(2-Fluorobenzyl)-4-(2-fluorobenzyloxy)benzaldehyde relative retention time is about 1.7 or 0 ~4-(3-fluiorobenzyloxy)benzaldehyde retention time is about 18 min;

N-

3- (3-fluorobenzyl) (3-fluorobenzyloxy) benzaldehyde relative retention time is about 1.7 3,4,5-trimethoxybenzaldehyde (IS) relative retention time is about 0.7.

Calculate the percent content of 3-(2-fluorobenzyl)-4-(2- 00fluorobenzyloxy)benzaldehyde in the 4- (2 -fluorobenzyloxy) benzaldehyde

(N

rn examined or of the 3-(3-fluorobenzyl)-4-(3-fluorobenzyloxy)benzaldehyde INO in the 4-(3-fluorobenzyloxy)benzaldehyde examined by internal standard calculation.

Cl 10 The value of the limit of quantitation (LOQ) for (3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzaldehyde and of 3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzaldehyde is 0.005% by weight. The value of the limit of detection (LOD) for both considered impurities is 0.0025% by weight.

EXAMPLE 17A HPLC determination Of Rurity of (S)-2-[4-(3-fluorobenzylogy) benzylaminolpropanamide (safinamide, 1a), its methanesulfonate (Ic) (S)-2-[4-(2-fluorobenzyloxy)benzvlaminoI~rovanamide (ralfinamide, 1b) and its methanesulfonate (1d).

The following chromatographic procedure is suitable for both the free base form (Ia, Ib) and the methane sulfonate salt (Ic, 1d) of the products.

Diluent Mobile phase.

Test solution Accurately weigh about 25 mg of product in a 25 ml volumetric flask, dissolve in and dilute to volume with diluent to obtain a solution having known concentration of about 1.0 mg/ml.

Chromatop-raphic condition N:\Meloume,\Case\Paen\7900-7999\P79432.AUSpec\P79432AU GM spoci Etr@L do 9/01/09 WO 2007/147491 PCTEP2007/005105 The chromatographic procedure is carried out by using: Column: Waters Symmetry C8, 150x4.6 mm, detection: UV 220 nm; column temperature: 30 0

C

mobile phase: 40% solvent A 10% solvent B 50% solvent C, containing 1.0 g/1 sodium octansulphonate; solvent A: Buffer solution KH 2

PO

4 0.05M; solvent B: Acetonitrile; sovent C: Methanol; isocratic elution, run time: 60 minutes; flow rate: 1.0 ml/min; injection volume 10 |1l.

Procedure Inject the test solution, record the chromatogram and calculate the product purity by area percent calculation.

(S)-2-[4-(3-Fluorobenzvlox)benzvlamino]propanamide (safinamide) and related impurities identification Retention time: (S)-2-[4-(3-Fluorobenzyloxy)benzylamino]propanamide retention time is about 5.5 min.

(S)-2-[4-(3-Fluorobenzyloxy)benzylamino]propionic acid relative retention time is about 0.73.

(S)-2-[3-(3-Fluorobenzyl)-4-(3-fluorobenzyloxy)-benzylamino]propanamide relative retention time is about 4.08.

(S)-2-[4-(2-Fluorobenzyloxy)benzylamino]propanamide (ralfinamide) and related impurity identification Retention time: (S)-2-[4-(2-Fluorobenzyloxy)benzylamino]propanamide retention time is about 5.5 min.

(S)-2-[4-(2-fluorobenzyloxy)benzylamino]propionic acid relative retention time is about 0.73.

(2 -fluorobenzyl) (2 -fluorobenzyloxy) benzylamino] propanamide relative retention time is about 4.08.

00

N-

rn EXAMPLE 17B IND HPLC determination of (S)-2-[3-(2-fluorobenzyI)-4-(2- 0 fluorobenzvloxvlbenzvlaminolpropanamide (free base, Ilb and Cl 10 methanesulfonate, lId) in fluorobenzylogy)benzylaminolpropanamide (free base, lb and methanesuffonate. Id) and of (S)-2-[3-(3-fluorobenzyI)-4-(3-.

fluorobengyloxvlbenzvlaminolpropanamide (free base, Ha and methanesulfonate. lIc) in (S)-2-i4-(3-fluorobenzvloxvlbenzvlaminol Rropanamide (free base, la and methanesulfonate, Ic) The determination of the (S)-2-[3-(2-fluorobenzyl) -4-(2-fluorobenzyloxy)benzylaminolpropanamide (free base and methanesulfonate) in (2 -fluorobenzyloxy) benzylamino] propanamide (free base and methanesulfonate) samples and of [3-(3-fluorobenzyl) (3fluorobenzyloxy)benzylaminolpropanamide (free base and methanesulfonate) in fluorobenzyloxy) benzylamino] propanamide (free base and methanesulfonate) samples is carried out according to the following conditions: Reference solution for the 13-(2-fluorobengl)-4-(2fluorobenzyloxy) benzvlaminol prop~anamide determination in the [4 -fluorobenzyloxcy) benzvlaminol propanamide: Accurately weigh about 30 mg of (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy) benzylamino] propanamide methanesulfonate reference N: Melboimease\ atnt\900 -7999\P1932AU\SpeC is\ P79432. AU GH noect firstdm 9/01/09 standard and 20 mg of (S)-2-[4-(2-fluorobenzyloxy)benzylamino] propanamide reference standard in a 50 mL volumetric flask, dissolve and dilute to volume with diluent; dilute 1.0 mL of this solution to mL with diluent (1st dilution); dilute 1.0 mL of the last solution to 20 mL with cdiluent (2nd dilution) to obtain a solution containing 00fluorobenzyl) -4 -fluorobenzyloxy) benzylaminolpropanamide (about 0. 12%) at about 1.2 0 N\ Melourmo\C..at\7900-7999\P79432.AU\Sp~cl.\P79432.AU GH SpeCd Eit-t.doc 9/01/09 WO 2007/147491 WO 207/17491PCT/EP2007/005105 }ig/ mL and -fluorobenzyloxy) benzylamino] propanarnide methanesulfonate at about 1. 00 pg/ mL (about 0. Reference solution for the (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzvloxvy~bengylaminolpropanamide methanesulfonate determination in the (SI -fluorobenzvloxyl benzvlaminoI propanamide methanesulfonate Accurately weigh about 30 mg of (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzylaminojpropanamide methanesulfonate reference standard and 20 mg of fluorobenzyloxy)benzylamino] propanamide methane sulfonate reference standard in a 50 mL volumnetric flask dissolve and dilute to volume with diluent dilute 1.0 mL of this solution to 20 mL with diluent (1st dilution); dilute 1.0 mL of the last solution to 20 mL with diluent (2nd dilution) to obtain a solution containing 2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy)benzylamino]propanamide about 0.15% as methanesulfonic salt) at about 1.20 pig/mL and fluorobenzyloxy)benzylaminolpropanamide methanesulfonate at about 1.00 pg/mL (about 0. Reference solution for the (S1 -2-[3-(3-fluorobenzvl)-4-(3fluorobenzvloxv)benzvlaminol prop~anamide in the (SI fluorobenzvloxvlbenzvlamino] propanamide: Accurately weigh about 24 mg of (S)-2-[3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzylamino]propanamide reference standard and 20 mg of -2-[4-(3-fluorobenzyloxy)benzylamino]propanamide reference standard in a 50 mL volumetric flask dissolve and dilute to volume with diluent; dilute 1.0 mnL of this solution to 20 ml with diluent (1st dilution); dilute ml of the last solution to 20 mL with diluent (2nd dilution) to obtain a solution containing 2- (3-fluorobenzyl) fluorobenzyloxy)benzylamino]propanamide about 0.12%) at about 1.20 pig/ mL and (3-fluorobenzyloxy) benzylamino] propanamide methanesulfonate at about 1. 00 p~g/ mL (about 0. WO 2007/147491 PCT/EP2007/005105 57 Reference solution for the (S)-2-[3-(3-fluorobenzyl)-4-(3fluorobenzvloxy)benzvlamino]propanamide methanesulfonate in the [4-(3-fluorobenzvloxv benzylamino]propanamide methanesulfonate: Accurately weigh about 24 mg of (S)-2-[3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzylamino]propanamide reference standard and 20 mg of (S)-2-[4-(3-fluorobenzyloxy)benzylamino]propanamide methanesulfonate reference standard in a 50 mL volumetric flask dissolve and dilute to volume with diluent dilute 1.0 mL of this solution to 20 mL with diluent (1st dilution); dilute 1.0 mL of the last solution to 20 mL with diluent (2nd dilution) to obtain a solution containing 2-[3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)benzylamino] propanamide (about 0.15% as methanesulfonic salt) at about 1.20 pg/mL and fluorobenzyloxy)benzylamino]propanamide methanesulfonate at about 1.00 pg/mL (about 0.10%).

Test solution: Accurately weigh about 25 mg of test product in a 25 mL volumetric flask, dissolve and dilute to volume with diluent to obtain a solution having known concentration of about 1.0 mg/mL.

Chromatoaraphic conditions: The chromatographic procedure is carried out by using: Column Waters Simmetry C8 150 x 4.6 mm, 5p or equivalent column temperature: 30 0

C

mobile phase: mixture of 40% solvent A: 10% solvent B 50% solvent C, containing 1 g/lt of sodium octanesulfonate solvent A: buffer solution 0.05M KH2PO4; solvent B: acetonitrile; solvent C: methanol; isocratic elution; run time: 60 min; flow rate: 1.0 mL/min; detection: UV 220 nm; injection volume: 100 pl; WO 2007/147491 PCT/EP2007/005105 ~VO (10714741 PCIEP207IO558 diluent :mobile phase Procedure: Inject blank (diluent), reference solution, test solution and record the chromatograms.

In the reference chromatogram. verify the following stistem suitabilitt parameters: (2-Fluorobenzyloxy)benzylamino]propanamide retention time is about 5.2 minutes; The USP tailing for [4-(2-fluorobenzyloxy) benzylamino] propanamide peak is in the range between 0.8 and [3-(2-Fluorobenzyl)-4-(2fluorobenzyloxy) benzylamino] propanamide relative retention time is about 5. 1.

or (3-Fluorobenzyloxy)benzylamino]propanamide retention time is about 5.5 minutes; The USP tailing for -[4-(3-fluorobenzyloxy) benzylaminol propanamide peak is in the range between 0.8 and (S)-2-[3-(3-Fluorobenzyl)-4-(3fluorobenzyloxy) benzylamino] propanamide relative retention time is about 4. 1.

Adjust the mobile phase in order to obtain the system suitability.

Calculate the percent content (S)-2-[3-(2-fluorobenzyl)-4-(2fluorobenzyloxy) benzylamino] propanamide free base and methanesulfonate in the examined (2 -fluorobenzyloxy)benzylamino] propanamide (free base and methanesulfonate) samples and of (S)-2-[3-(3-fluorobenzyl)-4-(3fluorobenzyloxy)bcnzylamino]propanamide (free base and methanesulfonate) in the examined fluorobenzyloxy)benzylamino]propanamide (free base and methanesulfonate) samples by external standard calculation.

The value of the limit of quantitation (LOQ) for (S)-2-[3-(2-fluorobenzyl)- 4-(2-fluiorobenzyloxy)benzylaminojpropanamide and for(S)-2-[3-(3fluorobenzyl) -fluorobenzyloxy) benzylamino] propanamide in the corresponding (2 -fluorobenzyloxy)benzylamino] propanamide and (S)-2-[4-(3-fluorobenzyloxy)benzylaminojpropanamide is 0.004% by 00 weight.

The value of the limit of quantitation (LOQ) for (S)-2-[3-(2-fluorobenzyl)- IO4- (2 -fluorobenzyloxy) benzylamino] propanamide methane sulfonate and for(S) [3-(3-fluorobenzyl) c-i 10 fluorobenzyloxy)benzylaminojpropanamide methanesulforiate in the corresponding (2 -fluorobenzyloxy)benzylamino] propanamide methariesulfonate and fluorobenzyloxy) benzylaminolpropanamide methanesulfonate is 0.005% by weight. The value of the limit of detection for all the considered 1s impurities is 0.00 1% by weight.

EXAMPLE 18 HPLC determination of (S)-2-i4-(2-fluorobenzylogy)benzvlaminoI Rropanamide (ralfinamide) methanesulfonate (Id) enantiomeric purity The enantiomeric purity of the sample is evaluated by HPLC. The determination is carried out according to the following: Standard solution 1: Dissolve about 5.3 mg of (R)-2-[4-(2-fluorobenzyloxy)benzylamino] propanamide methanesulfonate reference standard in 25 mL of mobile phase.

Standard solution 2: Dissolve about 8.0 mg of (S)-2-[4-(2-fluorobenzyloxy)benzylaminoI propanamide methanesulfonate reference standard and 0.2 mL of standard solution 1 in 50 mL of mobile phase.

The concentration of fluorobenzyloxy) benzylamino] propanamide methanesulfonate is about N:\elbumeCao.\atet\7000 999\7942.A\Seci\P 432AUCH speo1 fr doc 9/01/09 00.5% calculated with respect to the concentration of Sfluorobenzyloxy)benzylamino]propanamide methanesulfonate.

c- Test solutions 1 and 2: In duplicate, dissolve about 8.0 mg of the test product in 50 mL of mobile phase.

0 Chromatographic conditions: C Column: Chiralpak WH 250mm x 4.6mm, I.D. column temperature: 45 °C; 0- mobile phase: 0.25 mM CuS0 4 (accurately weigh about 40 mg of C- 10 CuS04 in 1000 mL of water)/MeOH 60/40; isocratic elution; flow rate: 1.0 mL/min; detection: UV 230 nm; injection volume: 10 pl; run time: 15 minutes.

Procedure: Analyse blank (mobile phase) once, standard solution 2 twice, test solutions 1 and 2 once and verify that: for the standard injections, the RSD% for fluorobenzyloxy)benzylamino]propanamide methanesulfonate percent area is less than both for standard and sample solutions, for each injection the main peak percent area is included between the average value 0.1%.

Calculate the (R)-2-[4-(2-fluorobenzyloxy)benzylamino]propanamide methanesulfonate content (percent area) as mean of the two determination.

Retention times: (S)-2-[4-(2-fluorobenzyloxy)benzylamino]propanamide retention time is about 5.7 min.

(R)-2-[4-(2-fluorobenzyloxy)benzylamino]propanamide relative retention time is about 1.7.

N:\Melboumne\Cseg\Patent\7900-79999\P79432 .AU\Speci.\P79432.AU G spect fir@Ldoc 9/01/09 EXAMPLE 19 HPLC determination of (S)-2-[4-3-fluorobenzyloxvibenzvlaminol Rropanamide (safinamide) methanesulfonate (Ic) enantiomeric purity 00 The enantiomeric purity of the sample is evaluated by HPLC. The

(N

rn determination takes place according to the following conditions: Test solution: Dissolve about 10 mg of test sample in 10 mL of mobile phase.

(1 10 Chromatographic conditions: N: Me bomeCaes\Patnt 7000-7999 P943. LISpe:1O\ 7R 32. UOH speci f~ra.do 9/01/09 WO 2007/147491 PCT/EP2007/005105 61 Column: Chiralpak WH 250mm x 4.6mm, I.D. column temperature: mobile phase: 0.25 mM CuSO4 isocratic elution; flow rate: 1.0 mL/min; detection: UV 200 nm; injection volume: 10 p1; run time 30 minutes.

Procedure: Inject the test solution and calculate the enantiomers peak response as area percent.

(S)-2-[4-(3-Fluorobenzyloxy)benzylamino]propanamide retention time is about 9.2 min.

(R)-2-[4-(3-Fluorobenzyloxy)benzylamino]propanamide relative retention time is about 1.9.

EXAMPLE Cytochrome P450 assay Inhibition of the five most important Cytochrome P450 isoforms (CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4), involved in drug metabolism, was measured using specific substrates that become fluorescent upon CYP metabolism (Gentest Kit assay).

Compounds were tested in a 96-well plate containing incubation/NADPH regenerating buffer. Specific human recombinant isoenzymes and substrates were added and incubated at 37 °C for 15 minutes for CYP1A2/CEC, 40 minutes for CYP2E1/MFC, 45 minutes for CYP2C9/MFC and 30 minutes for the others CYP450.

The specific substrates were the following: 3-cyano-7-ethoxycoumarin (CYP2C19 and CYP1A2), 7-methoxy-4-trifluoromethylcoumarin (CYP2C9), 3[2(N,N-diethyl-N-mwthylamino)ethyl]-7-methoxy-4-methylcoumarin (CYP2D6) benzylphenylcoumarin (CYP3A4) The plates were read on a Victor plate reader (Perkin Elmer) at the WO 2007/147491 PCT/EP2007/005105 62 appropriate emission/excitation wavelengths, and the ICso (concentration inhibiting by 50% the enzyme activity) determined. The results are reported in Tables 1 and 2.

EXAMPLE 21 Cytotoxicity assay in human neuroblastoma cell line SH-SY-SY At time zero, the cells were seeded at 1.10 4 /cm 2 in 96 well plates in DMEM growth medium 10% heat inactivated FBS 2mM 1-Glutamine 100U/mL 100jig/mL Penicillin/Streptomycin.

After 72 hours at subconfluent phase of growth, the medium was removed and cells were incubated for 24 hours at 37 °C in 180 pl of neurobasal medium 2 mM 1-Glutamine (Life Techonologies) with or without test compounds (20 p1, at least 5 concentrations in triplicate).

At the end of incubation, 20 pl of Alamar Blue dye (AlamarBlueTM Assay Kit, Promega) were directly added to the cell medium.

Four hours after, the cytotoxicity was assessed by measuring the fluorescence at 530 nm excitation and 595 nm emission using Tecan Spectrafluor plate reader.

Before and at the end of the treatment, the cultures were monitored microscopically by an Olympus IX70 inverted light microscope matched to an Image Analyzer (Image Pro Plus, 5.1) to evaluate the cellular morphology.

Results are epressed in Table 1 as concentration inducing 50% of mortality.

EXAMPLE 22 HERG current in transfected CHO cell lines The inhibition of HERG current was tested in CHO cells stably expressing recombinant HERG channel.

To evaluate the effect of the test compounds on HERG currents, cells were clamped at -80 Mv, depolarised to 0 mV for 5 seconds allowing activation of HERG current and repolarised to -50 mV during 5 seconds allowing HERG tail current to deactivate. This procedure was repeated at a frequency of 0.06 Hz. The current amplitude upon repolarisation (HERG tail current) was measured before and after exposure to the test compound.

0 Inhibition of current was calculated as the difference between the amplitude of HERG tail current amplitude measured at the end of external bath perfusion period and HERG tail current measured at the end of test compound perfusion period (when steady-state effect is reached) divided by control HERG tail current.

0 Drug concentration-inhibition curves were obtained by plotting tonic

(N

c blocks versus drug concentrations. Dose-response curves were fitted to I, the tonic block data, according to the logistic equation: y A2+(A1- A2)/[l+(x/IC 5 Al and A2 are fixed values of 0 and 1 corresponding C 10 to 0 and 100% current inhibition, x is the drug concentration, ICso is the drug concentration resulting in 50% current inhibition and p is the corresponding slope factor.

The results are reported in Table 1.

EXAMPLE 23 Maximal electroshock test (MES) in mice The maximal electroshock test (MES) is used commonly in the screening of anti-epileptic drugs in rodent models.

Animals and Apparatus: Male CD1 mice weighing 25 g were used. The procedure described by White et al. (White H. Woodhead J. H., Franklin M. Swinyard E. and Wolf H. H. Antiepileptic Drugs (1995) 4 th ed.: 99-110, Raven Press, Ltd., New York) was followed. An Ugo Basile electroconvulsive generator (Model ECT UNIT 7801) was used to deliver an electrical stimulus sufficient to produce a hindlimb tonic extensor response in at least 97% of control animals. The stimulus was delivered intra-aurally through clip electrodes in mice (0.7 seconds of a 40 mA shock, with a pulse train of 80 Hz having a pulse duration of 0.4 ms). The acute effect of compounds administered intraperitoneally or orally 15-60 minutes before MES induction were examined and compared with a vehicle control group. Ten mice were studied per group. Complete suppression of the hindlimb tonic extensor component of seizures was taken as evidence of anticonvulsant activity.

ti:\Mel boue\C-7999P7932AU\Specie\P79432.AU GH pecl ilre.doc 9/01/09 0The compounds of the invention were administered orally or Sintraperitoneally at the doses of 3-30 mg/kg.

The results are expressed in Tables 3 and 4 as of protection.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the 0 publication forms a part of the common general knowledge in the art, in c Australia or any other country.

IN In the claims which follow and in the preceding description of the Sinvention, except where the context requires otherwise due to express C- 10 language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

N:\elboume\Caae .\Patent\79000-79999\P9432.AU\Specl\P79432U GH speci flrrdc 9/01/09

Claims (45)

1. A process for producing high purity degree fluorobenzyloxy)benzylamino]propanamide (safinamide) and fluorobenzyloxy)benzylamino]propanamide (ralfinamide) of formula (Ia) O0 and (Ib) N NH 2 C F H safinamide 3-F ralfinamide 2-F and their salts with a pharmaceutically acceptable acid, characterized in that a Schiff base intermediate respectively of formula (VIa) or (VIb) F( D- CH= N NH 2 (VIa): 3-F (VIb): 2-F is submitted to catalytic hydrogenation with hydrogen gas in the presence of a heterogeneous catalyst in a protic organic solvent and, when safinamide or ralfinamide are obtained in a free base form, optionally converting said free base form in a salt thereof with a pharmaceutically acceptable acid.

2. A process as claimed in claim 1 wherein the catalytic hydrogenation is carried out by using an heterogeneous catalyst selected from nickel, rhodium, platinum and palladium catalysts on an inert support in the presence of a solvent selected from lower aliphatic N;Melbome\\Cses\Patet\79000-79999\P94 32.AU\Spec\P9432 .AU GH speci firt.cdoc 9/01/09 0 3. A process as claimed in claim 2 wherein the solvent is selected from methanol, ethanol and isopropanol.

4. A process as claimed in claim 1 wherein the catalyst is a palladium or platinum catalyst.

5. A process as claimed in any of claims 1 to 4 wherein the 0 catalyst is wet 5% Pt/C (50% H 2 0) or wet 10% Pd/C (50% H 2 0). c

6. A process as claimed in any of claims 1 to 5 wherein the I pharmaceutically acceptable acid is methanesulfonic acid.

7. A process as claimed in any of claims 1 to 6 wherein the C 10 hydrogen pressure is comprised between 1 and 10 bars and the temperature is comprised between 10 °C and 70 °C.

8. A process as claimed in claim 7 wherein the hydrogen pressure is comprised between 3 and 6 bars and the temperature is comprised between 25 °C and 40 °C.

9. A process as claimed in any of claims 1 to 8 wherein the catalytic hydrogenation is carried out on a Schiff base intermediate (VIa) or (VIb) which has been prepared through iminoalkylation of 4-(3- fluorobenzyloxy)benzaldehyde (IVa) or 4-(2- fluorobenzyloxy)benzaldehyde (IVb) CHO (IVa):3-F (IVb):2-F with L-alaninamide in the presence of a protic organic solvent.

10. A process as claimed in claim 9 wherein the L-alaninamide is employed as an acid addition salt thereof in the presence of a base in an amount sufficient to set free L-alaninamide from its salt.

11. A process as claimed in claim 9 where the catalytic hydrogenation of the Schiff base intermediate is performed on the same N:\Mlboum\Cae\Patet\79000-79999\P7943.AU\SpecIO\P79432.AU CH apeci fire.doC 9/01/09 0reaction mixture resulting from the completion of the iminoalkylation reaction under conditions which provoke the precipitation of said Schiff base intermediate to obtain a suspension of said intermediate in the same reaction solvent.

12. A process as claimed in claim 9 wherein the Schiff base 0 intermediate resulting from the completion of the iminoalkylation IN reaction is isolated before undergoing to the catalytic hydrogenation IN step.

13. A process as claimed in any of claims 1 to 12 wherein the 4- C 10 (3-fluorobenzyloxy)benzaldehyde or 4-(2-fluorobenzyloxy)benzaldehyde of formula (IVa) or (IVb) employed as the starting material to obtain the Schiff base intermediate of formula (VIa) or (VIb) contains less than 0.03% (by weight), of the respective impurities 3-(3-fluorobenzyl)-4-(3- fluorobenzyloxy)benzaldehyde (Va) and 3-(2-fluorobenzyl)-4-(2- fluorobenzyloxy)benzaldehyde (Vb). CHO %o F (Va):3-F (Vb):2-F

14. A process according to claim 13 wherein the 4-(3- fluorobenzyloxy)benzaldehyde (IVa) or 4-(2-fluorobezyloxy)benzaldehyde (IVb) is obtained by alkylation of 4-hydroxybenzaldehyde with, respectively, a 3-fluorobenzyl or 2-fluorobenzyl derivative (IIIa) or (IIIb) F (IlIa): 3-F (IIIb): 2-F N:\Melbouume\Caseo\Patent\79000-7999\P72.AU\Specis\P'9432.AU CH speci flr@L.dm 9/01/09 0 where Y is a leaving group, in the presence of a base and is submitted to crystallization before the use in the successive reaction step.

15. A process as claimed in claim 14 wherein Y is Cl, Br, I, OS0 2 CH 3 or OS02-C6H4-pCH3.

16. A process as claimed in any of claims 14 and 15 wherein the 0 crystallization is carried out by adding an inert organic non-solvent to a solution of the 4-(3-fluorobenzyloxy)benzaldehyde (IVa) or 4-(2- IN fluorobenzyloxy)benzaldehyde (IVb) in an inert organic solvent.

17. A process as claimed in claim 16 wherein the inert organic C- 10 non-solvent is selected from lower aliphatic hydrocarbons and the inert organic solvent is selected from aromatic hydrocarbons.

18. A process as claimed in claim 17 wherein the lower aliphatic hydrocarbon is n-hexane and the aromatic hydrocarbon is toluene.

19. A process as claimed in any of claims 13 and 14 wherein the crystallization is carried out by dissolving the 4-(3- fluorobenzyloxy)benzaldehyde (IVa) or 4-(2- fluorobenzyloxy)benzaldehyde (IVb) in a hot solvent and then cooling the solution at room temperature or below. A process as claimed in claim 18 wherein the hot solvent is cyclohexane, di(C 3 -C 4 alkyl ether.

21. A process as claimed in claim 18 wherein the hot solvent is diisopropyl ether which is at reflux.

22. A process as claimed in claim 18 wherein the solution is cooled at between 10 *C and 15 °C.

23. A process as claimed in any of claims 14 to 19 wherein the alkylation reaction is carried out under phase transfer conditions.

24. A process as claimed in claim 23 wherein the alkylation under phase transfer condition is performed in a solid/liquid system wherein the reagents and the phase transfer catalyst are dissolved in a liquid organic phase and the solid phase is constituted by an inorganic base or a salt of 4-hydroxy benzaldehyde with said inorganic base. N:\Meboumne\Ca.e.\Patent\7900-79999\P79432.AU\Specl.\P79432.AU GH Opoci flnt dc 9/01/09 L 0 25. A process as claimed in claim 23 wherein the alkylation under phase transfer conditions is performed in a liquid/liquid system -s wherein the alkylating reagent 3-fluorobenzyl or 2-fluorobenzyl C derivative of formula (IIIa) or (IIIb) is dissolved in a liquid organic phase and the 4-hydroxybenzaldehyde is dissolved in an aqueous phase as a 0 salt with an inorganic base. c 26. A process as claimed in any of claims 23 to 25 wherein the phase transfer catalyst is selected from quaternary ammonium or Sphosphonium salts or polyethyleneglycols of low molecular weight. Cl 10 27. A process of claim 26 wherein the amount of phase transfer catalyst employed is between 0.02 to 1 mole per mole of 4- hydroxybenzaldehyde.

28. A process as claimed in claim 27 wherein the amount of phase-transfer catalyst is 0.1 to 1 mole per mole of 4- hydroxybenzaldehyde.

29. A process as claimed in any of claims 24 to 28 wherein the organic solvent of the liquid organic phase is selected from dialkyl ethers and aromatic hydrocarbons. A process as claimed in any of claims 24 to 29 wherein the molar ratio between the alkylating reagent of formula (IIIa) or (IIIb) and 4-hydroxybenzaldehyde is comprised between 0.6 and

31. A process as claimed in any of claims 24 to 30 wherein the temperature is between 60 °C and 160 °C.

32. A process as claimed in any of claims 24 to 31 wherein the inorganic base is selected from Na2CO 3 K 2 C0 3 NaOH and KOH, the temperature is between 80 °C and 120 °C and the ratio between the alkylating reagent of formula (IIIa) or (IIIb) and 4-hydroxybenzaldehyde is comprised between 0.9 and 1.1.

33. A process as claimed in any of claims 1 to 32 wherein safinamide or ralfinamide or their salts with a pharmaceutically acceptable acid have a content of the respective impurity fluorobenzyl)-4-(3-fluorobenzyloxy)benzylamino]propanamide (IIa) and N:\Melbomne\C.es\Paent\79000-79999\P79432.AU\Spe\P79432.AU GH speci I rsrd0 9/01/09 I (S)-2-[3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)benzylamino]propanamide (IIb) (IIa) (IIb) or their salts with a pharmaceutically acceptable acid lower than 0.03% (by weight).

34. A process as claimed in claim 33 wherein pharmaceutically acceptable acid is methanesulfonic acid and the content of the respective impurity of formula (IIa) and (lib) as the salt with methanesulfonic acid is lower than 0.01% (by weight). The isolated Schiff base of formula (VIa) or (VIb) (VIa):3F (VIb):2F

36. High purity degree safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid with a content of the respective impurity (S)-2-[3-(3-fluorobenzyl)-4-(3- fluorobenzyl)benzylamino]propanamide (IIa) and fluorobenzyl)-4-(2-fluorobenzyloxy)benzylamino]propanamide (IIb) ti:\elboumne\Caae.Patent\79000-9999\P79432,AU\Speci\P9432. GH .peci I fl-.doc 9/01/09 I 00 (IIa) (IIb) M or a salt thereof with a pharmaceutically acceptable acid which is lower IN than 0.03% (by weight). 0 5 37. High purity degree safinamide or ralfinamide salt with a NC pharmaceutically acceptable acid as in claim 36 wherein the pharmaceutically acceptable acid is methanesulfonic acid and the content of the respective impurity of formula (IIa) and (IIb) as the salt with methanesulfonic acid is lower than 0.01% (by weight).

38. Use of high purity degree safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid wherein the respective impurity of formula (IIa) and (IIb) of claim 36 or a salt thereof with a pharmaceutically acceptable acid is lower than 0.03% (by weight) for the manufacture of a medicament for the treatment of respectively (a) epilepsy, Parkinson's disease, Alzheimer's disease, depression, restless legs syndrome and migraine or pain conditions including chronic and neuropathic pain, migraine, bipolar disorders, depressions, cardiovascular, inflammatory, urogenital, metabolic and gastrointestinal disorders under conditions that are not interfering with the cytochromes of the CYP450 system, in particular CYP3A4, CYP2D6, CYP2C19, CYP2C9 and do not exhibit HERG channel blocking properties.

39. Use of high purity degree safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid for the manufacture of a medicament for the treatment of disorders according to claim 38 in patients that are classified as poor metabolizers (PM) or for the therapeutical treatment of patients who are concomitantly assuming other drugs which are known to interact with the cytochromes of the N:\Melbour-n\CaBco\Patent\79000-79999\P79432.AU\Specia\P79432.AU GH speci firat.doc 9/01/09 0 CYP450 system and/or are known to have HERG channel blocking properties. -s 40. Use according to claim 38 and 39 wherein the pharmaceutically acceptable acid is methanesulfonic acid and the content of the respective impurity of formula (IIa) and (IIb) as the salt 0 with methanesulfonic acid is lower than 0.01% (by weight). (N

41. Use of high purity ralfinamide or a pharmaceutically IN acceptable acid addition salt thereof according to any one of claims 0to 39 for the manufacture of a medicament for treatment of a bipolar cN 10 disorder.

42. Use according to claim 41 wherein the pharmaceutically acceptable acid of ralfinamide is a methanesulfonic acid salt.

43. A pharmaceutical formulation containing high purity degree safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid wherein the content of the respective impurity of formula (IIa) and (IIb) of claim 36 or a salt thereof with a pharmaceutically acceptable acid is lower than 0.03% (by weight).

44. A pharmaceutical formulation of claim 43 wherein the pharmaceutically acceptable acid is methanesulfonic acid and the content of the respective impurity of formula (IIa) and (Ilb) as the salt with methanesulfonic acid is lower than 0.01% (by weight). A pharmaceutical formulation of claim 43 which contains one or more additional active agent(s) in addition to high purity degree safinamide or ralfinamide or a salt thereof with a pharmaceutically acceptable acid wherein the content of the respective impurity of formula (IIa) and (IIb) of claim 36 or a salt thereof is lower than 0.03% (by weight).

46. A pharmaceutical formulation of claim 45 wherein the pharmaceutically acceptable acid is methanesulfonic acid and the content of the respective impurity of formula (IIa) and (IIb) as the salt with methanesulfonic acid is lower than 0.01% (by weight). N:\Melbouu\Cau\PaTsnC\\790007999P932A\pP7P942A GH opeci flret.d 9/01/09 I

47. A pharmaceutical formulation containing high purity degree Ssafinamide or a salt thereof with a pharmaceutically acceptable acid according to any of claims 45 and 46 wherein the additional active agent is a dopamine agonist and/or levodopa and/or a catechol-O- methyltransferase (COMT) inhibitor. 00

48. A pharmaceutical formulation containing high purity degree c ralfinamide or a salt thereof with a pharmaceutically acceptable acid according to any of claims 45 and 46 wherein the additional active "1- Sagent is gabapentin or pregabalin or a pharmaceutically acceptable acid C 10 additon salt thereof.

49. A method for treating CNS disorders, in particular epilepsy, Parkinson disease, Alzheimer's disease, depression, restless legs syndrome and migraine comprising administering to a patient in need thereof an effective amount of high purity degree safinamide or a salt thereof with a pharmaceutically acceptable acid wherein the content of the impurity (S)-2-[3-(3-fluorobenzyloxy)-4-(3-fluorobenzyl)- benzylamino]propanamide of formula (IIa) /^NH2 F -oH O RN 0 (IIa) or a salt thereof with a pharmalceutically acceptable acid is lower than 0.03% (by weight). A method of claim 49 for treating Parkinson's disease or restless legs syndrome which comprises administering to a patient in need of said treatment an effective amount of high purity degree of safinamide or a salt thereof with a pharmaceutically acceptable acid wherein the content of the impurity of formula (IIa) or a salt thereof with a pharmaceutically acceptable acid is lower than 0.03% (by N:\melbou\Caae\Patenr\790D0-7999\P7943 .U\SPeCI\P7943 .AU G0 OPVCl flrecdo 9/01/09 I 0 weight), optionally in conjunction with one or more Parkinson's disease Sactive agent(s).

51. A method of claim 49 wherein the Parkinson's disease active agent is a dopamine agonist and/or levodopa and/or a catechol-O- methyltransferase (COMT) inhibitor. 0

52. A method as in any of claims 49 to 51 wherein the c pharmaceutically acceptable acid is methanesulfonic acid and the IN content of the respective impurity of formula (IIa) and (IIb) as the salt Swith methanesulfonic acid is lower than 0.01% (by weight). C' 10 53. A method as in claim 49 wherein the patient in need of the treatment is classified as poor metabolizer (PM) or is concomitantly 'assuming other drugs which are known to interact with the cytochromes of the CYP450 system and/or are known to have HERG channel blocking properties.

54. A method for treating pain conditions including chronic pain and neuropathic pain, migraine, bipolar disorders, depressions, cardiovascular, inflammatory, urogenital, metabolic and gastrointestinal disorders comprising administering to a patient in need thereof an effective amount of high purity degree ralfinamide or a salt thereof with a pharmaceutically acceptable acid wherein the content of the impurity 2-[3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)-benzylamino]propanamide of formula (IIb) SN NH 2 H (Ilb) or a salt thereof with a pharmaceutically acceptable acid is lower than 0.03% (by weight). A method as in claim 52 for treating pain conditions, including chronic pain and neuropathic pain, and migraine, optionally n° (lib) or a salt thereof with a pharmaceutically acceptable acid is lower than 0.03% (by weight). A method as in claim 52 for treating pain conditions, including chronic pain and neuropathic pain, and migraine, optionally N:\Melbourne\CaBes\Pacent\79000-79999\P79432.AU\SpecB\P79432.AU GH upeci flrt.doc 9/01/09 L 0 in conjuction with gabapentin or pregabalin or a pharmaceutically Sacceptable acid addition salt thereof.

56. A method as claimed in any of claims 52 and 53 wherein the salt of ralfinamide with a pharmaceutically acceptable acid is a salt with methanesulfonic acid and the content of the respective impurity of 0 formula (IIa) and (IIb) as the salt with methanesulfonic acid is lower rn than 0.01% (by weight). IND 57. A method as claimed in claim 52 wherein the patient in need Sof the treatment is classified as poor metabolizer (PM) or is C 10 concomitantly assuming other drugs which are known to interact with the cytochromes of the CYP450 system and/or are known to have HERG channel blocking properties.

58. A method as claimed in any of claims 52 and 55 wherein the patient is affected by a bipoler disorder.

59. A method as claimed in claim 56 wherein the salt of ralfinamide with a pharmaceutically acceptable acid which is administered to the patient affected by a bipolar disorder is a salt with methanesulfonic acid. A process for producing high purity degree safinamide and ralfinamide, the high purity degree safinamide and ralfinamide, methods or uses of the high purity degree safinamide and ralfinamide or a pharmaceutical composition comprising it or a Schiff base intermediate of formula (VIa) or (VIb) substantially as herein described with reference to the accompanying examples. N:\Melboume\C&.e9\Paent\7900-79999\P79432.AU\Spece\ P79432AU GH .peci firet.doc 9/01/09